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ON 



A TRUE PARTHENOGENESIS 



IN MOTHS AND BEES ; 



A CONTRIBUTION TO 



THE HISTORY OF REPRODUCTION IN ANIMALS. 



BY 



CARL THEODOR ERNST VON SIEBOLD, 

Professor of Zoology and Comparative Anatomy in the University of Munich, Knight 

of the Order of Maximilian, Director of the Zoological and Zootomical 

Cabinet, and Conservator of the Zoological Institute in Munich. 



TRANSLATED BY 
WILLIAM S. DALLAS, F.L.S. &c. 



LONDON: 
JOHN VAN VOORST, PATERNOSTER ROW 

MDCCCLVII. 



Non semel quEedam sacra traduntur ! Eleusin servat quod ostendat revisentibus. 
Rerum natura sacra sua non siraul tradit. Initiatos nos credinms: in vestibulo ejus 
baeremus. Ilia arcana non promiscue nee omnibus patent: reducta et in interiore 
sacrario clausa sunt. Ex quibus aliud hsec aitas, aliud, quae post nos subibit, 
dispiciet. — Seneca {Natural. Qucestion. lib. vii. 31). 



PREFACE. 



Engaged in constant efforts to trace and clear up the historj 
of animal reproduction, as far as this is permitted to human 
discernment, I have been guided to a phenomenon in Insect- 
life which had for a long time remained obscure to me, — I refer 
to the power of reproduction of some female Insects which 
remain unfecundated, as this not only appeared to be a great 
mystery, but even a fact never yet firmly established, and 
therefore still doubtful. I always found this so-called Lucina 
sine concubitu treated by physiologists as a sort of curiosity; 
the same examples from Insect-life, derived from the older ob- 
servers, were constantly referred to as vouchers. The question, 
whether the fact referred to was supported upon a firm basis, 
remained at the same time altogether unnoticed. As every kind 
of statement with regard to Lucina sine concubitu was received 
with so little caution and without suspicion, new observations 
were added to the older defective notices of this kind ; but these, 
in the same way, appeared inadmissible as soon as they were 
carefully analysed. 

Since the process of the fecundation of the egg has become 
much better understood by the recent discoveries of Newport, 
Keber, Bischoff, Leuckart, Meissner, and Bruch, one was com- 
pelled to say, that all the cases of Lucina sine concubitu observed 
in former or modern days might be founded upon delusion 
or error, because up to this time the knowledge of the con- 
ditions under which fecundation takes place was still extremely 
imperfect. Now, when the physiology of reproduction has 
been enriched with many exceedingly important discoveries, 
and by these some essential points in the act of fecundation, 

148739 



IV PREFACE. 

which had been previously overlooked, have been brought to 
light, very different claims are made upon those observations, 
by which it is to be decided, whether an egg which has arrived 
at development was or was not fecundated. 

For this reason I was not to be blamed if I made my first ap- 
pearance as a sceptic, and submitted this subject to an exami- 
nation corresponding with the present fundamental laws of 
Physiology. The results of this examination, contrary to ex- 
pectation, have furnished the proof :— 1. that a Lucina sine con- 
cubitu does exist ; and 2. that this does not merely start up here 
and there accidentally, as was formerly supposed, but that it 
occupies its perfectly definite position in nature. It is true that 
it still remains concealed from us, according to what laws and 
under what motives this remarkable mode of reproduction has 
obtained the place assigned to it in the history of reproduction. 

In these investigations, to which I have devoted the careful 
study of many years, I was very readily and disinterestedly 
assisted by various naturalists, who, partly by providing me with 
the materials necessary for such investigations and observations, 
but partly also by communicating their own multifarious expe- 
rience upon the department in question, put me in a position to 
obtain as wide a glance as possible over this still imperfectly 
explored field. I therefore regard it as my duty to express my 
public thanks here to Baron von Berlepsch of Seebach, MM. 
Bremi of Zurich, Dzierzon of Carlsmarkt, Professor F. de 
Filippi of Turin, Dr. Herrich-SchafFer of Ratisbon, Senator von 
Heyden of Frankfort a. M., M. Kollar, Director of the Imperial 
Cabinet at Vienna, MM.Radlkofer of Munich, Reutti of Frei- 
burg, Dr. Rosenhauer of Erlangen, A. Schmid of Eichstadt, 
Steiner of Breslau, and Professor Zeller of Glogau, for the 
assistance which they rendered me in my investigations. 

C. T. E. VON SlEBOLD. 
Munich, 25th March \S56. 



TRANSLATOR'S PREFACE. 



Of all the discoveries which have been made of late years in 
the history of the reproduction of animals, none is of greater im- 
portance than that of the entrance of the spermatozoids into the 
ovum, which is found to be the rule not only in the Animal, but 
also in the Vegetable Kingdom. Nevertheless, but a few years 
have elapsed since the final settlement of this disputed question, 
and we have in the following observations of Professor Siebold 
a clear proof of the occurrence of phenomena, which, if they do 
not invalidate the law, at least show that it is liable to some, 
probably to many exceptions. 

Several years ago our author published some observations 
upon a species of Psyche, which, as he stated, propagated without 
copulation. He referred this singular occurrence to the same 
class of phenomena as the asexual reproduction of the Aphides, 
the so-called Alternation of Generations ; and although it must 
have been evident to every one who attentively studied his paper 
that the circumstances of the two cases were widely different, it 
was impossible, in the state of our knowledge at the time, to 
propose any more satisfactory explanation of the phenomenon. 
Now, however, the whole face of affairs is changed. Von 
Siebold, as will be seen in the following pages, has clearly 
proved the existence of a sexual reproduction without fecunda- 
tion, not only in the Psychidce, to which his former observations 
related, but also in the Bees,— in both as a regular occurrence, 
and as an occasional phenomenon also in the Silk-worm Moth ; 
the latter circumstance giving a considerable degree of proba- 
bility to some even of those supposed cases which our author dis- 
cusses and rejects as inadmissible in the first section of his book. 
^For this phenomenon of reproduction by virgin females the 
author ado^yts the term Parthenot/encsis, originally proposed by 



vi translator's preface. 

Professor Owen to express the dissimilar Digenesis or Alternation 
of Generations. 

That the same thing occurs in other species of animals 
besides those upon which the author's observations have been 
made, there can be no doubt, and, in fact, several of these are 
indicated in his concluding remarks. Of some of the Ento- 
mostracous Crustacea no males have yet been detected, whilst 
the females of others have been observed to propagate without 
concourse with the male. A still more striking instance is 
afforded by the Gall-flies belonging to the restricted genus 
Cynips, of which several species are very common in Europe, 
and yet amongst the thousands which have been reared from 
galls, not a single male has ever been seen. An oak-gall has 
been found in great quantities of late in Devonshire, which has 
attracted considerable attention from those few Entomologists 
in this country who trouble themselves with the study of 
Hymenoptera. It is produced by a species of Cynips, and all 
the specimens, to the number of several hundreds, which have 
been reared, confirm the above statement as to the absence of 
males. Some experiments now being made by Mr. Smith of 
the British Museum, whose tact and power of observation so 
thoroughly fit him for the investigation of such a point, will 
probably soon determine whether these Insects are also to be 
cited in support of the interesting and important theory 
developed by Von Siebold in the following pages. Amongst 
the Entozoa, we may also probably meet with further instances 
of Parthenogenesis, as their propagation, notwithstanding the 
great advances that have of late been made in our knowledge 
of its phenomena, still presents much that is enigmatical. 

But it is not only in the Animal Kingdom that we meet with 
this phenomenon of ovular reproduction without impregnation : 
similar instances occur also amongst the Phanerogamous plants. 
Many years ago, Camerarius and Spallanzani asserted that the 
female Hemp was capable of producing fertile seed without the 
aid of the male pollen ; and a French botanist, M. Lecoq, has 
lately addressed a note to the Academy of Sciences, referring to 
some experiments made by him, and published in 1827, upon 
the same subject. His experiments were made upon various 
dioecious plants, amongst which Hemp, Spinach, Mer curtails 



translator's preface. vii 

annua, and Trinia vulgaris furnished him with fertile seeds, 
although every precaution was taken to isolate the plants. (See 
Comptes Rendus, 8th December, 1856, p. 1069.) A dioecious 
Euphorbiaceous plant also, the Ccelebogyne, from Australia, has 
produced fertile seeds in the Botanic Gardens at Kew, although 
only the female is known to botanists. 

Interesting as this curious discovery of Von Siebold's must 
be to the Physiologist, there are some points connected with it 
which render it of the highest practical importance to the 
keepers of Bees. The greater part of the following pages is 
devoted to the consideration of the wonderful series of phae- 
nomena presented by the reproduction of those industrious 
Insects, and the intelligent Bee-keeper will find that by studying 
it he will obtain many hints, which, if properly applied in prac- 
tice, may enable him not merely to study the habits of his in- 
teresting charges with much greater satisfaction than heretofore, 
but also, by proper management, to increase the profits derivable 
from his hives, — a consideration which may perhaps have more 
weight with many than any of a purely theoretical nature. 

Although I cannot flatter myself that I have done full justice 
to the exceedingly happy phraseology in which Professor von 
Siebold has communicated his results to the world, I have 
endeavoured as far as lay in my power to adhere strictly to the 
original, so that the English reader might at least be sure of 
getting the true sense of the author. 

The proof-sheets have been submitted to Professor Owen, who 
has kindly enriched them with some valuable notes, of which 
those relating to Hunter's views are especially interesting. The 
additional notes are all included between brackets. 

W. S. DALLAS. 



London, 20th January, 1857. 



CONTENTS. 



Page 

Introduction 1 

Elucidation of the Cases hitherto described as Parthenogenesis . . 12 

True Parthenogenesis in some Sac-bearing Lepidoptera 24 

True Parthenogenesis in the Honey-Bee 38 

True Parthenogenesis in the Silk-worm Moth 92 

Concluding Remarks 1 04 

Explanation of the Figures 109 



ON 



TRUE PARTHENOGENESIS. 



INTRODUCTION. 

It is high time that Zoologists and Physiologists should turn 
their attention to a phenomenon in the history of the re- 
production of animals, which, during the last few years, has 
warmly interested the Apiarians and set them in the greatest 
excitement, — I mean the mode in which each separate colony of 
Bees contrives that the worker-, drone-, and royal-cells prepared 
by it are always furnished with the proper eggs, from which, as 
is required by the arrangement of these different kinds of cells, the 
worker-larvae, drone-larvae, and queen-larvae destined to dwell in 
them, are always excluded. Hence the oviposition in the Bee-hive 
must be effected according to peculiar rules, in order that the 
conditions just mentioned may be fulfilled; this act of oviposition 
must be subjected to determinate laws, which do not affect the ovi- 
position of most other insects, as in these it is a matter of indif- 
ference in what consecutive order and number male and female 
eggs are laid. But the question, how each separate Bee-colony 
succeeds in obtaining the suitable supply of eggs for all its combs, 
differently as these are prepared as regards the number and 
arrangement of the three kinds of cells, has not been easily 
answered ; nay, we may perhaps say, that this process has hitherto 
appeared to be an impenetrable mystery, the solution of which 
has not been effected by the most careful endeavours and observa- 
tions of the Apiarians continued for many years. This mysterious 

B 



2 INTRODUCTION. 

circumstance, which distinguishes the oviposition of the Bees, has 
also been the cause that, from time immemorial, the Apiarians have 
been disputing about the signification of almost every individual 
step in the process of reproduction in the Bees. This contest 
has continued even to the present day, and it is scarcely possible 
to imagine a single absurdity with regard to the history of the 
reproduction of the Bees, which has not already been expressed 
in sober earnest by some Apiarian, and is not to be read in print 
in one of the innumerable Bee-books. The greatest confusion 
especially was caused by the circumstance, that people could 
not agree with regard to the sexes of the Bees ; the Drones 
were regarded as females and the Queens as males ; sometimes 
it was supposed that the Workers alone had the care of the 
oviposition ; sometimes the true act of copulation between the 
drones and the queen was supposed only to take place in the 
interior of the hive ; the wedding-flight of the queen would then 
only be a sort of purification ; whilst from another side it was 
asserted that the act of copulation was never performed in the 
hive, but always high up in the air during the wedding-flight. 
The act of coition was also entirely denied, the queen becoming 
fertilized by the mere agitation of her body during the wedding- 
flight. I could fill many pages here with these contradictions, 
which are deposited in the annals of the history of Bee-life, and 
by which the study of this otherwise so interesting subject from 
books, has been stunted into a most ungrateful task. 

This endless dispute about the reproduction of the Bees, 
often carried on with great animosity, in which the opponents of 
the different theories of generation relating to the Bees often 
showed themselves to be mere dilettanti, miserably furnished 
with natural- history information, was not fitted to attract the 
interest of physiologists ; indeed, it appeared as if the Apiarians 
wished to fight the battle out amongst themselves without 
foreign assistance, for the contest was never brought within 
the province of an earnest -investigation of nature. Moreover, 
the naturalists could not very easily take part in the dispute, 
as they were mostly deficient in the practical knowledge of 
the oeconomy of Bees, without which every attempt to settle 
the matter must have turned out imperfect, and would have 
been received with distrust by the obstinate Bee-masters, to 



INTRODUCTION. 



whom such an attempt might have served as an instructive 
hint. In this dispute of the Apiarians, which was constantly 
blazing up afresh, the activity of the naturalists limited itself 
to their ascertaining and establishing as an incontestable truth, 
by the aid of the dissecting-knife and the microscope, that the 
drones are the male individuals, that the queen is the female 
individual, and that the workers are not merely asexual, but 
female individuals, the reproductive organs of which had not 
come to their full development. Upon this subject, investiga- 
tions were made and published by the zootomists at very dif- 
ferent periods. I refer only to the works of Swammerdam*, 
Reaumur f, Mademoiselle JurineJ, Suckow§, and Ratzeburg||. 
Although the representations of the male and female sexual 
organs of the Bees have been copied from Swammerdam's Biblia 
Natures by various writers upon these insects, and consequently 
the facts established anatomically were communicated to the Api- 
arians, yet for a long time these truths could not boast of a re- 
cognition by all Bee-keepers. These entomotomic investigations 
probably did not appear sufficiently significant to the Apiarians, 
because there were still many things in the history of tHe re- 
production of the Bees, which could not be explained with this 
knowledge of the sexual relations of these animals. Many 
practical Apiarians looked upon this anatomical proof of the 
sexes of Bees merely as theoretical stuff, and returned to their 
so-called practical way, which they imagined to be the right one, 
without regard to these facts, preferring to explain the different 

* Bibel der Natur, 1752, pp. 188 & 202, taf. 19 & 21. 

t Memoires pour servir a VHistoire des Insectes, tome v. 1/41, pi. 32-34, 
which portion appeared in 1759 translated into German under the title of 
" Geschichte der Bienen." 

I Vide Huber, Nouvelles observations sur les Abeilles, 2de edit. 1814, p. 431 . 
pi. 11. fig. 1. In this work are deposited the interesting anatomical investiga- 
tions of the above-mentioned lady, by whom the existence of abortive ovaries 
in the Worker-Bees was first ascertained; they are represented in an admirable 

figure prepared by herself. 

§ Heusinger's Zeitschrift fur Organische Physik, Band ii. Heft 3, 1828, 

p. 231. taf. 12. fig. 30, taf. 14. fig. 38. 

|| Brandt und Ratzeburg, Medizin. Zoologie,\833, p. 202. taf. 25. figs. 34,35, 
as well as Ratzeburg's Untersuchung des Geschlechtszust andes In i den soge- 
nanntenNeutris der Bienen unduber die Verwandtschaft derselben mit den I\ imtg- 
innen, 1833, in the Nova Acta Physico-Medica, vol. xvi. pt. ii. p. 613. tab. 1, . 

B 2 



4 INTRODUCTION. 

sexual functions in a perfectly arbitrary and unnatural fashion, 
according to their own individual and often very limited views. 

After I had, in the year 1837^ ascertained the existence and 
signification of the seminal receptacle in female insects*, and in 
1843 called attention to this reservoir of semen in the Queen- 
Bees f, by the functions of which many phenomena in the repro- 
ductive activity of the Bees, which had hitherto remained pro- 
blematical, or had been incorrectly explained, might be properly 
conceived, these investigations exerted no particular influence 
upon the perverted views of most of the Apiarians. They pro- 
bably paid no further attention to them, as theoretical stuff, and 
yet, by the recognition of the function of the seminal receptacle, a 
phenomenon in the Bee-hive, which had been a source of wonder 
from time immemorial, could now be correctly explained. Thus, 
it had been ascertained by me, that after copulation had taken 
place, the semen of the drone, which filled the seminal receptacle 
to overflowing, remained in this place, capable of impregnating 
the eggs, not merely for months, but for years, as might be seen 
from the movements of the spermatozoids of this semen con- 
tinuing for that period J. This explains how a queen, fertilized 
by a single coitus, after discharging her eggs in the first year, 
may again, in the following year, and even still more frequently, 
lay eggs capable of development, such as the hive requires, as 
fertilizing semen is still constantly preserved in her seminal re- 
ceptacle, to fecundate eggs even for so long a period. But even 
this discovery w r as ignored by most of the Apiarians ; as a general 
rule, fresh scruples as to the value of such anatomical and micro- 
scopical investigations were constantly rising amongst them, with 
respect to the determination of the sexual functions of the Bees. 

There were two phenomena especially in the oeconomy of the 
Bees, which troubled the minds of the Apiarians with reference 
to the division of the sexual functions in those insects, — I 
mean, 1. the capability of an imperfect- winged female to pro- 
duce brood, and 2. the production of brood in a queenless 

* See my Observations upon the Spermatozoa in fecundated female Insects, 
in Miiller's Archiv, 1837, p. 417. 

f Ueber das Receptaculum seminis der Hymenopteren- Weibchen, in Germar's 
Zeitschrift fur die Entomologie, Bd. iv. 1843, p. 371. 

X See Germar's Zeitschr. loc. cit. p. 374 (with regard to Apis mellifica), 
and Wiegmann's Archiv, 1839, i. p. 107 {Vespa rufa). 



INTRODUCTION. 



hive. Those who acknowledged the Queen as the female indi- 
vidual of the Bees, and, in accordance with the physiological 
laws hitherto current, ascribed to her the property of laying 
eggs capable of development only after previous copulation and 
the filling of the seminal receptacle with spermatozoids, were, 
in consequence of the first-mentioned phenomenon, rendered 
doubtful where and when the copulation of the Queen-Bee is 
effected. From this arose the dispute, so abundantly battled 
out in the books and journals relating to Bees, as to whether 
the Queen copulates in or out of the hive. That the former was 
possible was thought to be proved by the imperfect-winged 
Queens laying eggs capable of development, and thus the two 
sexes of Bees were supposed to perform the act of copulation in 
the interior of the Bee-hive, although such a copulation in the 
hive had never been seen. In this respect the Bees shared the 
same fate with the Roes ; in these animals the practical game- 
keeper could not comprehend why, after the single rutting time 
(in August and September), the uterus of the Roe contained 
no embryo, and therefore incorrectly ascribed a second rutting 
time (in December) to the Roes, although no one had met with 
Roes in copulation during that period. In those cases in which 
the second remarkable phenomenon previously mentioned oc- 
curred, namely, brood in a queenless Bee-hive, we should entirely 
mistake the sexual functions of the Bees. Such observations 
were principally employed in raising objections of insufficiency 
and untenabilitv against the scientific endeavours at the determi- 
nation of the sexes of Bees. 

In most Zoological or Entomological works we find all these 
acrimonious controversies regarding Bee-life, either imperfectly 
mentioned or scarcely indicated, and hence it may have hap- 
pened, that the history of the reproduction of the Bees has 
remained untouched by those physiologists who have specially 
occupied themselves with the generation of animals*. On this 
side no one had any idea what difficult problems are here pre- 
sented to science for solution. Moreover the physiologists were 
lately engaged by another very attractive but also very difficult 

* In the ample article upon Propagation (Zeugung) by 11. Leuckart (see 
R. Wagner's Handwdrterbuch der Physiologie, Bd. iv. 1853), the remarkable 
history of reproduction in the Bees is scarcely touched. 



INTRODUCTION. 



subject, which incited them to inquire after the laws, according 
to which the asexual reproduction, previously regarded as an 
exception and now characterized by the name of Alternation of 
Generation, occurs disseminated amongst the lower animals, 
together with sexual generation. 

By the entomologists the physiology of reproduction has been 
very scantily enriched of late, as most of them found their task 
only in rectifying the species of Insects ; many of them endea- 
voured, at the expense of much time and trouble, to determine 
those species which have been furnished with names by Linnaeus 
and Fabricius, whilst the majority found a still greater pleasure 
in enriching the systematic catalogues of Insects with a few 
perfectly new, although extremely insignificant species. 

As up to a very recent period the Apiarians formed a sort 
of close corporation, wishing to answer the most important 
questions relating to the reproduction of the Bees amongst 
themselves, it may thus have happened that the fruits with 
which the knowledge of the history of reproduction was enriched 
by the labours of modern naturalists, could not be perceived at 
all by this close and short-sighted circle, and consequently could 
not be made use of by them. Nor did any voice ever force its 
way out of their circle which might have called in the assistance 
of the physiologists in the decision of certain problems in the re- 
production of the Bees. Only within the last three years has the 
demeanour of the Apiarians changed in a most satisfactory way, 
and it must be said, in praise of the present circle of Apiarians, 
that at this moment it numbers amongst its members, men who 
have arrived at a conviction that Bee-life does not merely serve 
to furnish man with wax, honey and mead, but that it consti- 
tutes an extremely remarkable link in the great and most multi- 
fariously composed chain of animal existence, the importance of 
which, however, can only be understood by the assistance of 
knowledge such as is furnished by the present development of 
the Natural Sciences. By the activity of these enlightened men 
a complete revolution has taken place in Bee-keeping ; a rational 
process introduced by the Apiarians, and rewarded by the richest 
results, now celebrates the most complete triumph over empiri- 
cism, and in this the names of Dzierzon and Berlepsch above 
all deserve to be named as conquerors. 



INTRODUCTION. 7 

I believe I ought to give some information as to the way in 
which I have been induced to take part in this active movement 
of the Apiarians, as reference is made hereafter to a new theory 
of reproduction applying to the Bees, the defence of which I 
have undertaken, not however from a preconceived opinion forced 
upon me from without, but from an internal conviction springing 
from the course of my own investigations and observations. 
From the following pages the reader will understand how the 
investigation of the history of reproduction in Insects necessarily 
led me to the natural history of the Bees. 



Probably within the last few years no branch of the history 
of animals has been enriched by new discoveries, and the am- 
plification and completion of old observations, in so high a 
degree as the theory of animal reproduction. A mass of facts 
which were in direct contradiction to the theoretical laws so 
long established as the rules for the propagation of animals, and 
which previously had scarcely any value but their curiosity, 
have been united by the piercing eye of Steenstrup under the 
name of Alternation of Generations* to form a law, w r hich is 
now found by naturalists to prevail in all directions. There was 
previously a long series of remarkable observations, against the 
correctness of which, as they stood in contradiction to the laws 
of reproduction previously adopted as the rule, doubts might 
willingly have been raised, if the stamp of truth had not been , 
impressed upon them by the credibility of their observers. 
From many of these observations, over which a naturalist here 
and there was every now and then shaking his head in incre- 
dulity f> all doubt has been now cleared away by the recognition 

* Steenstrup, Ueber den Generationswechsel, Copenhagen, 1842. 

f This negation of the processes connected with the alternation of genera- 
tions is expressed even in the most recent times, in the views by which Ehren- 
berg and Diesing explain the nature of the Cercarice. Although direct 
observations and the most careful investigations have shown that these re- 
markable asexual creatures are not perfect animals, but belong, as larvae, in 
the developmental series of certain Trematode worms, Ehrenberg sticks stead- 
fastly to his opinion, that the Cercarice only present a distant similarity to 
the Trematoda (see the Bericht iiber die zur Bekanntmachung geeigneten Ver- 
handlungen der Akad. der Wiss. zu Berlin a. d. J. 1851, p. 77o"), and re- 
proaches Steenstrup with having allowed himself to be misled into tin 



8 INTRODUCTION. 

of the alternation of generations. Other observations which 
still remain problematical, the results of which also will not 
accord with the fundamental laws of the history of reproduction 
as at present known, will probably, as we must hope, be here- 
after lighted up by the rays of the alternation of generations. 
Nevertheless from my own investigations I have also come to 
the conviction, that on the other hand we must not expect too 
much from the alternation of generations^ as when we wish and 
imagine it, we do not always obtain an explanation from it. I 
must give especial warning against following an investigation 
too far with the preconceived notion that we have to do with an 
alternation of generations, as otherwise we may be led widely 
astray upon a false course, and never find the right way. 

Not to deviate too far from the object which I have set before 
me in these pages, I will only here give prominence to that in 
the history of Insects which people have been induced to regard 
as a peculiarity of the alternation of generations, — I mean the 
remarkable reproduction of the Aphides ; this, after standing so 
long as something quite abnormal and inexplicable, has now 
found its complete explanation in the nature of the alternation 
of generations. It is well known that in the Aphides, a sexual 
generation, represented by separate males and females, is followed 
by a series of generations, only including a single form, which 
proceed from each other in manifold repetition without any pre- 
vious copulation, until after about seven to eleven such genera- 
tions, a generation of males and females again makes its appear- 
ance. Steenstrup* regarded these forms of Aphides, which are 
capable of reproduction without the influence of the male gene- 
important error of supposing that the Cercarice became developed into 
Distoma by casting off their tails. Ehrenberg at the same time refers to his 
exposition, description and figure of the Cercaria Ephemera, given in the year 
1828 (Symbolce Physica, Phytozoa Entozoa), which to his regret has not 
been referred to by Steenstrup, and which would probably have preserved him 
from some errors. In this description, however, Ehrenberg has declared the 
excretory organ representing a primordial kidney to be ovaries, and its coarsely 
granular contents, eggs, to which I have long since called attention (see my 
Lehrbuch der vergleichenden Anatomie der Wirbellosen, p. 139). Diesing, no 
less consistently, holds fast by the belief that the Cercarice are an independent 
and closed group of animals (see his Revision der Cercarien, in the number for 
March 1855 of the Sitzungsberichte der Akad. der Wiss. in Wien). 

* Op. cit. supra, p. 121. 



INTRODUCTION. 9 

rative organs, and which had previously been looked upon as 
virgin female Aphides, as Nurses [Ammeri), and consequently as 
those members of an animal-species subjected to an alternation 
of generations, which are capable of producing young in the 
asexual (or larval) state. Those Aphides which bring forth living 
young without a preliminary copulation, are in reality quite dif- 
ferent in their organization from the true female Aphides, which 
lay eggs capable of development after the act of copulation. In 
the viviparous Aphides those organs especially from which the 
living young are produced, have quite a different form and organi- 
zation from the sexual organs of the oviparous female Aphides, 
so that, in opposition to the ovaries (Eierstocke), the products of 
which (eggs) only become capable of development by the action 
of the male semen, we may with perfect justice indicate these 
organs as germ- stocks (Keimstocke), which are capable of pro- 
ducing young of themselves, without the influence of male fer- 
tilizing organs. These nurse-like, viviparous Aphides therefore, 
which instead of ovaries bear germ-stocks in their interior, are 
also destitute of the seminal receptacle, which occurs universally 
in the females of Insects and plays an important part in the act 
of fecundating the eggs*. Before the alternation of generations 
had yet been introduced into science by Steenstrup, I had al- 
ready called attention to the different conditions of organization 
in the oviparous and viviparous Aphides, and especially to the 
absence of the seminal receptacle in the latter f. Subsequently 
the development of the Aphides without fecundation has been 
completely explained by V. CarusJ as a process of the alterna- 
tion of generations. The representation which Carus has given 
of the development of germinal bodies in the germ-stocks of the 
viviparous Aphides, has certainly met with a refutation from 
Leydig§, against which I have nothing to object; nevertheless, 
although, according to Leydig, the young are developed from 
the germ-bodies of the viviparous Aphides exactly as from eggs, 
by cell- formation, I would retain the denominations "germ- 

* See my Observations on the Spermatozoa in fertilized female Inserts. 
Miiller's Archiv, 1837, p. 392. 

t See Froriep's Neue Notizen, Bd. xii. 1839, p. 308. 

X Zur ndheren Kenntniss des Generationswechsels, 1849, p. 20. 

§ Bemerkungen uber die Entwickelung der Blattluuse in Siebold and Kol/i- 
ker's Zeitschrift fur wissenschaftliche Zoologie, i860, p. G'2. 



10 INTRODUCTION. 

body " and K germ-stock " for these reproductive organs of the 
viviparous Aphides, in order to distinguish them, on account of 
their different physiological import, with regard to the alterna- 
tion of generations, from the eggs and ovaries of the oviparous 
female Aphides. 

Owen* has regarded the asexual viviparous Aphides as virgin 
females capable of reproduction ; but these viviparous Aphides 
indicated by Owen as virgin parents are certainly something 
very different from the oviparous Aphides in their virgin state 
before copulation. For the same reason also I cannot approve 
of Owen's expression Parthenogenesis, as applied by him to the 
alternation of generations, as under the term Parthenogenesis I 
do not understand reproduction by asexual nurse-like or larval 
creatures, but a reproduction by actual females, that is to say, 
by individuals furnished with perfectly developed, virgin female 
organs, which produce eggs capable of development without pre- 
vious copulation and in an unfecundated condition. 

* On Parthenogenesis, or the successive production of procreating indivi- 
duals from a single ovum. London, 1849, pp. 30, 60, & /6. 

[By reference to this work, it will be seen that, in the description of the 
parthenogenesis of the Aphides, the viviparous individuals are called * larvae,' 
and the basis or blastema of the virgin-progeny ( germ-masses' : both are ex- 
pressly distinguished from the true ova and oviparous females. 

" The facts are briefly these : — 

" The impregnated ova of the Aphis are deposited at the close of summer, 
in the axils of the leaves either of the plant infested by the species or of some 
neighbouring plant, and the ova, retaining their latent life through the winter, 
are hatched by the returning warmth of spring : a wine/less hexajwd larva is 
the result of the development. This larva, if circumstances, such as warmth 
and food, be favourable, will produce a brood, and indeed a succession of 
broods of eight larvce, like itself, without any connection with the male. In 
fact, no winged males at this season have appeared. If the virgin progeny 
be also kept from any access to the male, each will again produce a brood of 
the same number of Aphides; and carefully prosecuted experiments have 
shown that this procreation from a virgin mother will continue to the seventh, 
the ninth, or the eleventh generation, before the spermatic virtue of the 
ancestral coitus has been exhausted. When it is so exhausted, a greater 
proportion of the nuclear germ-masses retained by the last procreant larva? is 
used up: individual growth and development proceed further than in the 
parent : some members of the last larval brood are metamorphosed into winged 
males, others into oviparous females. By these the ova are developed, im- 
pregnated, and oviposited."— Owen's ' Parthenogenesis,' p. 23.] 



INTRODUCTION. 11 

This last mode of reproduction has been denominated Lucina 
sine concubitu by the older naturalists, a term, which must not 
be applied, as has been done by Owen, to the alternation of 
generations, the reproduction taking place in this case under 
totally different conditions, namely by division, by gemmation, 
or by germ-bodies, which are not to be confounded with eggs, as 
in all these modes of propagation the immediate influence of the 
male fertilizing elements is wanting, and this has not been acci- 
dentally or abnormally omitted, but, as is proved by the whole 
course of development of these generations, remains out of action 
in accordance with certain laws. 

As, with reference to my subsequent statements, I must lay 
a particular stress upon the distinction between the Alternation 
of Generations and Parthenogenesis, I repeat once more, that the 
viviparous Aphides are not virgin females which produce eggs 
capable of development without copulation, but that they are 
asexual, nurse-like or larval individuals, furnished with germ- 
stocks, which are as different as possible from the true virgin 
female Aphides*. 

* [The author of the term ' parthenogenesis/ which was devised to replace 
a phrase both cumbrous and incorrect, or at best only partially agreeing with 
the phenomena referred to in the text, believed it to be, etymologically, appli- 
cable to the male as well as the female, or the neuter. 6 napOevos is ' a young 
unmarried man,' just as fj vap&evos is 'a maid': irapdeveia, < virginity, purity,' 
is predicable of either sex, or of a generative individual of no sex. The term 
'parthenogenesis' was by no means proposed, as Siebold seems to imagine, 
under the idea that the virgin procreative Aphis was a perfect female, and its 
brood produced from eggs. Previously to the appearance of the book so 
entitled, Professor Owen had published the results of observations showing 
that the virgin Aphides developed their brood from nucleated cells, forming 
< germ-masses,' not from eggs (Lectures on Invertebrata, 1843); and the 
difference between the larviparous virgin and the oviparous wife in the Aphis 
tribe is given in detail. He defines < parthenogenesis' to mean ' procreation, 
without the immediate influence of the male,' as, e.g., spontaneous fission, 
gemmation, development from germ-cells and germ-masses, or from umm- 
pregnated ova. Should physiologists prefer, however, to limit the term as 
proposed by Professor Siebold, they will probably concur in the desirability of 
some other single word as an equivalent to < Alternation of Generations. By 
< metagenesis' is meant the sum of those changes which certain species undergo 
in the progress, through successive individuals, from the ovum to the perfect 
impregnating and egg-producing form.] 



12 



ELUCIDATION OF THE CASES HITHERTO DESCRIBED AS 

PARTHENOGENESIS. 

Since the remarkable reproductive history of the Aphides 
must be transferred into the domain of the Alternation of Gene- 
rations, it becomes a question whether we are not acquainted 
with other facts in the history of Insects, which are to be re- 
garded as Lucina sine concubitu or Parthenogenesis. In point of 
fact, observations have been published by the most different 
Entomologists of old and modern times, which should lead us to 
infer the pretty widely diffused existence of a true Partheno- 
genesis amongst Insects. But all these narratives of female 
Bombyces and other moths, which, when kept isolated and with- 
out any copulation, laid eggs from which young were afterwards 
excluded, require a more exact investigation ; for before we 
allow an important physiological law, derived from multifarious 
observations, to be thrown down by such statements, it is ne- 
cessary to determine, whether we can put implicit faith in 
these narratives, whether we have to do here with credible facts, 
or whether, in this case, a fact has not been rather concluded 
from superficial, unsatisfactory and scanty observations, than 
positively proved. I have already indicated these cases*, as 
being such as to require an exact investigation, to get rid of every 
doubt as to the assertion that a spontaneous evolution of brood 
can really take place in the eggs laid by virgin female insects. 
I had at that time proposed to myself to submit the cases brought 
forward by so many naturalists and narrated again and again, by 
which the existence of a Lucina sine concubitu was to be proved, 
to a careful criticism. This criticism I will now undertake, in 
order to show how little of all these assertions remains admis- 
sible ; for as we have to do with the maintenance or abolition of 
a physiological theoretical law, the importance of which has long 
been recognized, it follows as a matter of course, that none but 

* See Zeitschrift fur wissenschaftliche Zoologie, 1849, p. 97. 



D. H. HILL LIBRARY 
ttarth Caro'ira r /iafe College! 



SUPPOSED CASES OF PARTHENOGENESIS. 13 

perfectly credible observations and such as exclude all doubt can 
be admitted as of sufficient weight to abolish the law : — that true 
eggs (produced in an ovary) cannot become developed into an 
embryo, until they have first been exposed to the fertilizing in- 
fluence of the male semen (produced in testes). 

The oldest communication relative to the reproduction of fe- 
male insects sine concubitu, and one which has been repeatedly 
quoted, is due to the surgeon J. P. Albrecht of Hildesheim, who, 
in the year 1701, sent in to the Leopoldine Academy of Natu- 
ralists, a memoir with the title* " De Insectorum ovis sine praevia 
maris cum fcemella conjunctione nihilominus nonnunquam foe- 
cundis." In this memoir Albrecht relates that he took a brown 
pupa, which had spun itself up on a black-currant bush, and pre- 
served it under a glass in his summer-house, to see what moth 
would be evolved from it. At the end of July a moth of a yellow- 
ish-white colour escaped from it ; this is not more particularly 
described, but as Albrecht has compared it with the Moth figured 
by Godart in his Metamorphosis et Historic/, Insectorum (Pars I.) 
on tab. 33, we may suppose that it was either a Bombyx or a 
Noctua. This moth in a few days laid a great number of eggs 
and then died. Upon this Albrecht has the following remark : — 
"Cum masculum huic papilioni haud adfuisse certus essem et 
propterea ejus ova sub vent anea et sterilia esse judicarem, vix 
amplius eorum habui rationem, relictis interim iisdem oscitantius 
et sine omni cura sub dicto vitro per totum tempus hyemale." 
It was only in April of the following year that Albrecht again 
looked after the glass, and was astonished at finding young black 
caterpillars in it instead of the eggs. As Albrecht has given no 
exact description, either of the nature of the glass, or of the mode 
in which it was closed, and did not watch either the glass or its 
contents with the necessary care, it does not appear from this 
case, whether the openings of the glass in which the moth was 
kept were closed in such a manner that no male moth of the 
same species could have found admittance and an opportunity of 
copulating with the enclosed female. The same surgeon also 
mentions a Spicier, which had been in the possession of Dr. 
St. Blancard, and which for four consecutive years laid eggs 

* See Miscellanea curiosa sive Ephemeridum Academics Ctcsar. Leopold. 
Natur. Curios. Dec. iii. Annus ix. & x. 1706, p. 26. 



14 SUPPOSED CASES OF 

from which young Spiders escaped, although no male Spider 
had ever appeared in the business*. This short communi- 
cation gives us not the smallest information upon the question, 
whether this fertile Spider was actually taken in the virgin 
state, and whether her seminal receptacle may not have been 
filled with semen, before her capture, by a male Spider. Pre- 
cisely the same remarks will apply to that female Spider which 
Dumeril saw in Audebert's possession tj and which produced 
brood for two years when imprisoned, without the assistance of 
a male. That the male semen preserved in the seminal recep- 
tacle of the female insect retains its fertilizing power for years, 
is an ascertained fact; we know, for example, of Queen-Bees, 
that after a single copulation they may be fertile for four or five 
years ; and upon this point I may appeal to the testimony of 
the Pastor of Carlsmarkt in Silesia, M. Dzierzon J, whom I 
have learnt to know and value as one of the most experienced 
and credible Bee-keepers, amongst living Apiarians. Another 
observation of spontaneous reproduction sine concubitu, made 
by Basler upon a female of Gastropacha quercifolia bred from 
the caterpillar, is very briefly communicated by Bernoulli §. 
As in this case we neither find any mention of how long it was 
after the exclusion of the moth before Basler found it, nor 
any account of the secure preservation and shutting up of 
the pupa, a number of objections may be raised against the 
supposed Parthenogenesis in this case, on the ground of the 
deficiency of all exact details. No less inadmissible appears 
the case observed and communicated by Bernoulli himself as one 
of Parthenogenesis || . He had allowed a caterpillar of Episema 
caruleocephala to change to the pupa state, but afterwards left 
the pupa in a box without paying any further attention to it ; 
in about fifteen days he opened the box for the first time, and 
was surprised to find in it, besides the excluded moth which 

* This observation was first communicated in the Miscellanea curiosa, Dec. 
iii. Annus iii. 1696, p. 63. 

t See Dictionnaire des Sciences Naturelles, torn. ii. 1816, p. 324. 

X See his Theorie mid Praxis des neuen Bienenfreundes, 2 Aufl. 1849, pp. 
104 & 111. 

§ See Nouveaux Memoires de V Academie Royale des Sciences et Belles- 
Lettres, Annee 1772. Berlin, 1774, pp. 24 & 34. 

|| Op. cit. supra, p. 25. 



PARTHENOGENESIS. 15 

was dead, a family of young caterpillars which had already de- 
voured the pupa-case of their mother and a portion of their own 
egg-shells. The untenability of the assertion that, in the cases 
just mentioned, a Lucina sine concubitu took place, has already 
been proved with such convincing reasons by the Theresian 
professors [Denis and Schiffermuller), that I cannot do better 
than appeal to the arguments which the learned Viennese 
entomologists carried out in the following words*: — 

"We have too often observed that males have found their 
way to females which had been excluded in our rooms, and were 
perhaps even stuck upon a pin, and copulated with them, when 
we did not at all expect it, and frequently only observed it 
accidentally and late, and we have hardly observed this more 
with any species than with the very two species of Bombyces 
(in our catalogue, Fam. J. No. 1 and B. No. 1 t) which according 
to the naturalists above mentioned laid fertile eggs without copu- 
lation ; of the latter species indeed, we have frequently exposed 
a female designedly in the evening at the open window, in order 
to take males, which our friends required, and generally with 
the desired result. The narratives even of both the learned men 
appear to us not quite to exclude such an unperceived accident, 
or an accidental confusion or mistake. Herr Basler did not 
imprison the pupa but the excluded female in a glass (certainly 
as soon as he observed it), and left the eggs lying uncared for, 
upon a stone, until November; moreover he did not rear the young 
caterpillars ; and Herr Bernoulli let the pupa with the box go 
out of his sight until he found caterpillars already in it. Lastly, 
these very two species have often been reared by Reaumur, 
Rosel and other naturalists, and in very considerable numbers 
by ourselves; and would they not once have asserted their 
power of propagating without copulation, if they really possessed 
it? and yet, the females which did not copulate, never laid 
anything but barren eggs.' 5 Pastor von Scheven also has, with 
great tact, weakened the statements of Basler and Bernoulli, 
as proofs of the occurrence of a Lucina sine concubitu, by the 

* See Systematisches Verzeichniss der Schmetterlinge der Wiener Gegend, 
herausgeyeben von einiyen Lehrern am K. K. Theresianum, 177<>. p. 293- 

t The Theresian Professors mean hereby Gastropacha quercifolia and Sa- 
turnia pyri. 



16 SUPPOSED CASES OF 

following objections *: — " Even the most learned naturalist, often 
without noticing it himself, comes to the false conclusion : I 
have not observed this or that, therefore it has not taken place. 
Herr Basler's moth, as the narrative itself shows, was not of 
sufficient importance to him for exact observation, until he had 
recognized it as a hermaphrodite, by the supposed wonderful 
issue. But who is to give us security that a copulation and 
fecundation did not previously take place? In all probability Herr 
Basler only reared a single moth of this species, from which he 
came to the conclusion that no copulation had been possible. 
But how easily it may have happened that a copulation never- 
theless took place without his knowledge, the following obser- 
vations which I had the opportunity of making some years ago 
upon the Phal.Quercus, Linn., may distinctly show. Of this moth, 
I also had only a single caterpillar, which is figured by Rosel in 
the first part of his Insecten-Belustigungen, tab. 35#, and obtained 
from it a female moth. But as this came out of its cocoon just 
in the evening, I allowed it to creep up to the top of a window 
in my room, so that it might expand its wings properly, and as 
it behaved quietly, I allowed it to remain there through the 
night. The next day I perceived a male of this moth in the 
corner of the room, at which I was greatly astonished, as I 
knew with certainty that I had not had more than a single 
caterpillar of this moth in my house. However, I had not to 
wait very long for the solution of the riddle. For soon after- 
wards, thinking I heard a tapping at the window several times 
repeated, and opening the window to discover the cause of it, 
I soon perceived that several moths were flying about before it ; 
and although, from their rapid flight, I did not at once recognize 
them for what they were, I concluded from their strong flight, 
which they occasionally directed straight against the window, that 
they had something to seek there. I consequently did not allow 
them to knock long in vain, but opened some windows for them, 
upon which several males of this moth soon came into my room, 
and quickly discovering the female endeavoured to copulate 
with her. This history not only shows how strong is the scent of 
the male moths of this species and how great is their copulative 

* Beitr'dge zur Naturgeschichte der Insekten. Naturforscher, Stuck 20, 
1784, p. 50. 



PARTHENOGENESIS. 17 

impulse, but it also leads us to suppose that the same thing 
may have befallen Herr Basler, whose moth belongs to the same 
class with ours, and is closely allied to it in its nature and mode 
of life. For if the first male which found its way into my room, 
and which, no doubt, had slipped in through a small opening in 
the window, had immediately copulated with the female, and 
afterwards concealed itself in a corner of the room, or flown 
away again, and the following day had not been so fine, so as to 
give the opportunity for the above observations, I should have 
obtained fertilized eggs from my moth, in exactly the same way as 
Herr Basler, without thinking that a fecundation had taken place, 
and perhaps without thinking an error possible." Bernoulli's 
observation also is cleared up by Von Scheven with such weighty 
objections, that every trace of credibility is entirely wiped out of 
it. As Scheven has treated the subject with that felicity of 
expression peculiar to his time, it would require too much space 
if I were to reproduce his polemics in their full extent ; I shall 
therefore only quote the most important part of his observations. 
Amongst other things in Bernoulli's relation it had struck 
Scheven, that in fifteen days after the spinning up of the cater- 
pillar the little caterpillars had already escaped from the eggs, 
for which reason he expresses himself upon this point as follows*: 
" In the ordinary course of nature the caterpillar takes some 
days before it becomes converted into a pupa in its cocoon. 
The pupa usually lies at least fourteen days, and for the most 
part still longer, in its cocoon, before the moth makes its ap- 
pearance from it. But still more time is required, before the 
young caterpillars come to maturity in their eggs and creep out 
of them. The greater or less warmth of the season, or of the 
place where the pupee and eggs are kept, certainly often gives 
rise to a change in the duration of the time appointed for these 
events. But that all these changes should occur within fourteen 
days, is just as incredible as that a maiden, who has never seen 
a man in her life, and for still greater security has gone into a 
nunnery, can give birth to a child there, in an innocent way, 
within fourteen weeks. In all probability another female moth, 
which the author may have had long previously in this box, and 

* Loc. cit. p. 5-1. 



18 SUPPOSED CASES OF 

which may even have been of a different species (for the observer 
does not appear to have carefully examined the young caterpillars, 
which indeed are not easily known in their youth), had laid 
her eggs in one of the corners of the box, which the possessor 
had forgotten, or never observed. From these the young cater- 
pillars probably made their appearance, just at the time when 
the Phal. pacta* laid her unfertilized eggs; from want of 
nourishment they devoured the still fresh and soft eggs, and 
finally fell upon the pupa, or rather the pupa-case. This or some 
other mistake, of which many may be imagined, may have 
happened ; but this much is certain, that the history even in 
the way in which it is related and explained, deserves no credit, 
and that the conclusions built upon it must be proportionably 
incorrect." 

I could not refrain from reproducing the objections which 
Scheven urged against the observations published by Bernoulli, 
literally, as far as space w T ould permit, as they have hitherto re- 
mained quite unnoticed ; for as often as it was asserted that 
certain insects could lay eggs capable of development without 
previous impregnation, reference was always made, even in the 
most recent timesf, to the observations published by Bernoulli, 
which however had long before been invalidated as inadmissible 
by Scheven. 

Just as little value attaches to the other statements which 
are supposed to serve as vouchers for the existence of a Lucina 
sine concubitu, as, being in the form of very short notices, they 
also offer not the slightest security as to what precautions, if any, 
were taken to avoid the mistakes which so easily slip into such 
observations. For this reason we can attach no weight to the 
case which Suckow has communicated without any further 



* For what reason Scheven indicates the moth upon which Bernoulli made 
his supposed observation upon spontaneous reproduction as Phal. pacta, I do 
not know, for Bernoulli compares his moth with the Noctua figured by Rosel 
in his Insectenbelustigungen, iv. Sammlung, No. 15, which is nothing but Epi- 
sema cceruleocephala. 

t With regard to this compare G. R. Treviranus (Biologie, Band hi. 1805, 
p. 265) ; Burmeister (Handbuch der Entomologie, Bandi. 1832, p. 33/); Lacor- 
daire (Introduction a V etude de V Entomologie, torn. ii. 1838, p. 383) ; and 
V. Carus (Zur n'dheren Kenntniss des Generationswechsels, 1849, p. 21). 



PARTHENOGENESIS. 1 ( J 

particulars in the following words* : — u I have reared females of 
Bombyx Pini, which, without any previous copulation, laid eggs 
from which the caterpillars were developed, and passed through 
all their transformations." Another case was mentioned by 
L. C. Treviranus in these wordst: — " I have mvself been an 
eye-witness, that a female of Sphinx Ligustri, which had been 
developed from the pupa in my room during the night, and was 
impaled upon a pin the next morning, laid numerous eggs on 
the second day, from which caterpillars were evolved, exactly in 
the same way as if a copulation with a male had taken place, 
which most certainly was not the case." But when we remem- 
ber what is stated above by the Theresians and Scheven, Trevi- 
ranus' simple assurance, that in the case of this female Sphinx 
no copulation took place, will not suffice to remove all doubts 
as to whether a male may not have come secretly and unobserved 
and effected a copulation with this female, which might have 
escaped the observation of Treviranus the more easily as he cer- 
tainly did not previously think of a Parthenogenesis, or watch 
the impaled female very closely. Still more unsatisfactory are 
the very short statements of BurmeisterJ, in which nothing 
further is said than that Dr. Al. von Nordmann observed a spon- 
taneous development not long before in Smerinthus Populi, and 
that a similar instance was known in Gastropacha potatoria. 
Lacordaire's statements § also, regarding Lucina sine concubitu in 
Gastropacha Pint, and a case observed by Carlier, according to 
whom three generations were produced from a specimen of Liparis 
dispar without copulation, can only be received with distrust, 
as we look in vain in them for any exact description of the em- 
ployment of any of those precautions which are necessary in 
such observations. 

Another case of Parthenogenesis is said to have been observed 
by Plieninger ||. He had reared several females of Gastropacha 

* See Heusinger's Zeitschriftfur die organischePhysik, Band ii. 1828, p. 263. 

t See his Vermischte Schriften anatomischen und physiologischen Inkalts, 
Bandiv. 1821, p. 106. 

X Handbuch der Entomologie, Band i. p. 33/. 

§ Introduction, torn. ii. p. 383. 

|| See Wurtembergische naturwissenschaftliche Jahreshefte, Heft i. 1848. or 
Schleiden und Froriep's Notizen aus dm Gebiete der Natur- und HeUhatde, 

Band vii. 1848, p. 232. 

C 2 



20 SUPPOSED CASES OF 

Quercus from the caterpillars, and pinned them immediately 
after their exclusion. These deposited their eggs whilst impaled 
upon the pins, and of these a great part were fertile, although in 
this case, as Plieninger asserts, no fecundation had taken place. 
He adds that the fertile eggs were distinguished from the barren 
ones by their not collapsing like the latter, but retaining their 
convexity until the exclusion of the young caterpillars. Whether 
Plieninger actually watched for and saw the young caterpillars 
quit their eggs, has not been mentioned. But even if we sup- 
pose that the exclusion of the caterpillars really took place in 
the present case, this phenomenon will certainly have come un- 
expectedly upon Plieninger, and he will have omitted to guard 
the impaled females with the necessary care, until the act of ovi- 
position, against the access of males. 

I must still refer to two cases which have commonly been cited 
as evidence of a Lucina sine concubUu^ but which upon closer 
examination have nothing whatever to do with our question. 

One of these cases relates to the Bombyx, Orgyia gonostigma, 
the apterous female of which, Godart reared from the caterpillar* 
and saw it lay fertile eggs without copulation, a statement which 
not only astonished Godart, but also Listerf and GoezeJ. But 
Swammerdam§ and Reaumur || have already stripped all the 
marvellous from this relation, by showing that Godart had not 
recognized the winged individuals of this species as the males 
belonging to this moth, so that, without suspecting it, he had at 
the same time reared the males of the species, which very probably 
might have given occasion to a copulation with this female un- 

* See Metamorph. et Hist. Nat., pars secunda, de Insectis, 1662, p. 106. 
Experim. xxx. 

t J. Goedartius, de Insectis cum notularum additione. Opera Lister. 1685, 
No. 78 6. p. 190. 

X See his Entomologische Beitrage, Band iii. Th. iii. 1781, p. 9. I must, 
however, remark here, that Goeze has incorrectly quoted from Lister (Godart) 
No. 78 a and b to Bombyx antiqua, instead of No. 79. In a copy of Gbdart's 
Metamorphosis with coloured figures, which I have now before me, it is per- 
fectly clear that the moths and caterpillars copied from it in Lister's edition, 
Nos. 78 a and b, belong to Orgyia gonostigma, and No. 79 to Orgyia antiqua. 

§ See Biblia Natures, 1752, pp. 15 & 227. 

|| See Memoires pour servir a I'Histoire des Insectes, torn. i. part. i. 1737, 
12mo, p. 409. 



PARTHENOGENESIS. 21 

perceived by him. The other case which is also usually reckoned 
as a proof of a Parthenogenesis, relates to the observations made 
by Pallas* upon Psyche graminella and Fumea nitidella, to which 
I shall hereafter pay a closer attention (p. 24). Those cases of 
Lucina sine concubitu which are supposed to have been observed 
in Bees and Gall-flies, are also passed over here, as I must sub- 
sequently subject them to a separate criticism. 

If we glance once more over all the cases hitherto referred to, 
which were supposed to give evidence of a Parthenogenesis, the 
whole of them agree in that the soi-disant spontaneous evolution 
of the brood was noticed accidentally and unexpectedly by the 
observers, so that all those precautions which are necessary for 
the attainment of a certain observation fulfilling all the require- 
ments of science, were entirely neglected. For this reason, 
therefore, we must doubt the correctness of the consequences 
which the above-mentioned naturalists have derived from their 
observations, and the more so, as we can directly oppose to these 
observations^ others which were made from the commencement 
with the view of obtaining a certainty with regard to the possi- 
bility of a spontaneous development of the unfertilized eggs of 
insects, and which, with the employment of all the necessary 
precautions, have only furnished negative results. As evidence 
of this I may cite the multifarious observations of Reaumur, 
Rosel, and the Theresians, who never obtained caterpillars from 
the eggs laid by unimpregnated female moths. Direct experi- 
ments in rearing caterpillars from the unimpregnated eggs of 
moths have been made by Kefersteinf, according to his own 
statements, in which however he always came to a negative re- 
sult. But there is an observation made by Blancard and Aude- 
bert upon Parthenogenesis in Spiders which may even be placed 
in opposition to the above-mentioned inadmissible observations, 
and this shows that the Spiders also are subjected to the general 
physiological laws in their reproduction. BlackwallJ, namely, 

* See Nova Acta Physico-medica Academics Natures Curiosorum, torn. iii. 
1767, p. 430: " Phalsenarum biga, quarum alterius Femina artubus prorsus 
destitute nuda atque vermiformis, alterius glabra quidem et impennis, attamen 
pedata est, utriusque vero, sine habito cum masculis commercio, fepcunda ova 
par it." f See Entomologische Zeitung, 1842, p. 90. 

X See Annals of Natural History, 1845, vol. xv. p. 227- 



22 SUPPOSED CASES OF 

reared several young females of Agelena labyrinthica, Teyenaria 
domesiica and Teyenaria civilis in a perfectly isolated condition, 
and imprisoned in transparent glasses ; when these, after years 
of care and feeding, had become full-grown, they laid eggs in 
their virgin state, from which no brood was evolved. 

The negative results obtained by these direct observations of 
themselves furnished a sufficient ground for doubting the cor- 
rectness of the cases of pretended Parthenogenesis above referred 
to ; but the most convincing proof that observations of this kind 
in general, which are only made by accident, and not designedly 
contrived, must be received with the greatest distrust, as on such 
occasions mistakes so easily slip in, is furnished by the following 
epistolary communications. I am indebted to Herr W. von 
LangsdorfF, of Lahr, for the following note : — " A female of 
Gastropacha Quercus was evolved, which I took out of the 
breeding-cage standing in my garden and carried into my 
cabinet, which lies behind two rooms, where I placed it in an 
open box ; the doors stood half open, as it was the height of 
summer and very hot ; when I returned some time afterwards, 
I found this female Bombyoc in copulation with a male, which, 
however, flew away swiftly on my arrival ; this female of course 
laid fertilized eggs, whilst other females of G. Quercus which 
were excluded soon afterwards, and which I had carefully im- 
prisoned, certainly laid eggs, but these subsequently shrivelled 
up, as they were unimpregnated. Now, had I come a little later, 
when the male had already flown away, I should probably have 
been deceived also, as the female Bombyx was in exactly the same 
position as that in which I had placed it, and I could not have 
supposed that a male Oak moth could slip so unperceived through 
two rooms, in which there were several persons at the time, into 
a third." Herr von Heyden wrote me a little while ago : " It is 
remarkable, besides, with what acuteness certain male moths 
scent out their females. Many years ago I saw 7 a number of 
males of Psyche pulla swarming about a closed window in my 
sitting-room, and some of them settling on the panes. My 
attention being attracted by this, I perceived that females of this 
species had been evolved in a box standing in the room near the 
window. I was acquainted with no locality for this species in 
the neighbourhood of my dwelling." How easily, even in this 



PARTHENOGENESIS. 23 

case, if the windows had been imperfectly closed, might a copu- 
lation of the female Psyches have been possible and yet have 
remained unobserved ! What unexpected errors one may be 
exposed to in such observations, is also shown by a communica- 
tion made by Lucas*, according to which a male and female 
moth were evolved from two pupae of the silkworm enclosed in a 
common cocoon. It might be possible, if perchance both the 
moths in such a common cocoon quitted their pupa-cases simul- 
taneously, that they might have copulated in the interior of the 
cocoon notwithstanding the narrow space ; and if then the female 
alone had quitted the cocoon and laid eggs capable of develop- 
ment, how easily might the still-concealed male have been over- 
looked, and the case itself regarded as one of reproduction sine 
concubitu ! 

* See Annates de la Societe Entomologique de France, torn. iii. 1845, p. lxxxn. 



24 



TRUE PARTHENOGENESIS IN SOME SAC-BEARING 

LEPIDOPTERA. 

From the statements previously published I was unable to 
convince myself, that the possibility of a true Parthenogenesis in 
the insect-world was established beyond all doubt. In what 
way the observations so constantly repeated of a Parthenogenesis 
in the Psychidce were to be received and explained, I have shown 
in a previous memoir in the Zeitschrift fur wisseaschaftliche 
Zoologie*. A mistake is the more possible in this case, as the 
excluded footless females of the genus Psyche copulate in the 
interior of their former caterpillar-sac, and after the performance 
of the copulation creep back again into the pupa- case, in order to 
store it with fecundated eggs. A fertilized female Psyche of this 
kind, which has retired completely into her pupa-case, has often 
been regarded as an unexcluded virgin individual, whose power of 
laying eggs capable of development could not but excite the 
astonishment of those who were unacquainted with the mode of 
life of the true Psychce, but could not in the least surprise any one 
who was familiar with these mysteries. The Sac-bearers which 
are separated from the true Psychides according to the modern 
system and referred to the genus Fumea, may also give rise to 
similar errors, as, although their females, which are furnished 
with six legs, do certainly quit the former caterpillar-sac after 
their exclusion, and await the males clinging firmly to the out- 
side of the sac by means of their laying- tube, yet, after copula- 
tion has taken place, they stuff the pupa-case, which remains in 
the sac, so completely from top to bottom with eggs and wool 
from the extremity of their abdomen, that the full pupa-case, the 
cleft thorax of which is thus completely pressed together and 
consequently appears to be closed, may very easily be confounded 
with a still unexcluded pupa. 

After I had called attention to these important facts in the 

* Band 1. 1849, p. 93, " On the Reproduction of Psyche." 



PARTHENOGENESIS IN LEPIDOPTERA. 25 

history of the Psychidce, I nevertheless received assurances from 
various Lepidopterologists that they had notwithstanding ob- 
served a Parthenogenesis in the Psychidce, and felt certain that 
they had made no mistake. All the more exact statements 
referred to species of Sac-bearers, which are no longer considered 
as true Psychidce, but are placed amongst the Tineida, as the 
genus Tal&poricL) or more properly Solenobia. 

I felt myself incited by such communications to turn my 
most particular attention to these little Sac-bearers, which I had 
previously taken but little notice of, in which, being then in 
Freiburg, I had to congratulate myself on the assistance of 
Herr Reutti, a very able and credible Lepidopterologist. The 
two species, Solenobia lichenella, Linn, and Solenobia trique- 
trella, Fischer von Roslerstamm*, which are very abundant in 
the immediate vicinity of Freiburg, offered themselves to our 
observation, and of these, after my removal from Freiburg to 
Breslau, I found I was able to make use of many specimens 
at the latter place ; in Berlin also I collected at two different 
times a great number of sacs of these two Solenobice, so that 
during the years 1850, 1851, and 1852, I got together several 
hundreds of these sacs, but to my greatest astonishment none 
but female individuals were excluded from these sacsf? and only 
a single locality furnished me with a couple of males of Solenobia 
triquetvella. 

I was enabled to observe that these virgin female Sac-bearers, 
which I constantly watched in little vessels closed with glass- 
lids, clung firmly to the outside of their sacs, in the same 
fashion as the females of Fumea nitidella, and filled the sac with 
eggs by pushing in their laying-tubes ; however, these female 
Solenobice differed from the female Fnmece in this respect, that 
the former in escaping and creeping out dragged the pupa-case 
with them quite out of the sac. The pupa-case then remained 

* In regard to the determination of these two species of Sac-hearers, I refer 
to Zeller's classical description of the genera of Tineacea, in the Linncea 
Entomologica, Band vii. 1852, p. 343. 

f Wocke also collected about GOO sacs of Solenobia lichenella in the vicinity 
of Breslau, from which he did not obtain a single male. See the thirty-first 
Jahresbericht der Schlesischen Gesellschaft fur vaterldndisclie Cultur uber das 
Jahr 1853, p. 182. 



26 PARTHENOGENESIS IN SOME 

at first sticking loosely into the posterior free opening of the 
sac, which was firmly spun clown, but also frequently fell down, 
so that the female Solenobice always lay their eggs immediately 
in the sac itself. The females of the sac-bearing genus Talce- 
poria, which approaches most closely to Solenobia, proceed in 
exactly the same way in escaping and laying their eggs. 

But what particularly struck me in the behaviour of the female 
Solenobice, was the circumstance that they commence the busi- 
ness of oviposition very soon after their exclusion, whilst the 
females of Fumea put off their egg-laying until they have copu- 
lated, by which means many of the latter in my breeding-cages, 
in which there was sometimes a deficiency of males, died of 
vain expectation in their virgin state, without having previously 
discharged their eggs. The female Solenobice, on the contrary, 
possessed such a violent impulse to lay their eggs, that when I 
removed them from their sacs, they pushed their laying-tube 
about in search of the orifice of the sac, and at last let their 
eggs fall openly. If I had wondered at the zeal for oviposition 
in these husbandless Solenobice, how was I astonished when all 
the eggs of these females, of whose virgin state I was most 
positively convinced, gave birth to young caterpillars*, which 
looked about with the greatest assiduity in search of materials 
for the manufacture of little sacs ! 

After I had been first surprised by this phenomenon in the 
spring of the year 1850, I could not but be convinced that De 
Geer, Scriba, and Speyer, who reported that these animals laid 
fertile eggs without previous copulation, had not deceived them- 
selves, as I previously supposed f; nevertheless, I could not 
persuade myself that this phenomenon was to be explained as 
Parthenogenesis, but rather thought I recognized in the whole 
phenomenon, an asexual propagation analogous to the repro- 
duction of the Aphides, regarding the female Solenobice which 
had laid eggs capable of development without copulation as 
asexual nurses. In this way I quieted myself with the idea that 
an alternation of generations occurred in the insect-world, not 

* This production of fertile eggs without previous copulation has also been 
observed in Solenobia lichenella by Wocke {op. cit. supra, p. 182) and Reutti 
(see Beitrage zur rheinischen Naturgeschichte, Heft 3, 1853, p. 1/6). 

t See my memoir above referred to, on the Reproduction of Psyche, p. 99. 



SAC-BEARING LEPIDOPTERA. 27 

only amongst the Aphides, but also amongst some moths*. 
Subsequently, however, the thought occurred to me, that by the 
careful dissection of these questionable Solenobia-nurses, a much 
greater anatomical difference ought to be exhibited between 
them and the females of Solenobia than between the Aphis- 
nurses which produce living young and the egg-laying female 
Aphides f ; for it is well known that all female Lepidoptera 
possess two sexual orifices, one behind the other, of which the 
extreme or hindmost one serves for the deposition of the eggs, 
whilst the second orifice, placed before this (anteriorly), has to 
receive the male generative organ during the act of copulation. 
If these moths which laid eggs capable of development were 
nurses, I expected, on examining them carefully, to find neither 
the second sexual orifice on the exterior, nor the copulative 
pouch (bursa copulatrix) and seminal receptacle in the interior, 
parts which I had previously found in all female Lepidoptera J. 
I was, however, quite deceived in my expectations, for all those 
Talceporia which had been at first regarded by me as nurses, 
proved, without exception, to be perfectly developed female 
moths ; they all possessed the double sexual orifice, the copulative 
pouch, and seminal receptacle, arranged and developed in the 
same way as in other female Lepidoptera. The copulative pouch 
and seminal receptacle were always empty and unexpanded. 
Moreover no difference was discoverable (as to number, form 
and contents) between the ovaries of these supposed nurses and 
the same organs in other female Lepidoptera ; in short, I con- 
vinced myself in the most positive manner, that in this case we 
had nothing to do with nurses, but with virgin females §. 

After this discovery, the name of Parthenogenesis, which the 
English naturalist Owen applied to the alternation of genera- 
tions, must be peculiarly the most suitable denomination for the 

* See my Bemerkungen uber Psychiden, in the Jahresbericht der Schhsis- 
chen Gesellschaft fur vaterldndische Cultur uber das Jahr 1850, p. 84 ; re- 
printed in the Entomol. Zeitung, 1851, p. 341, and in the Transactions of the 
Entomological Society of London, vol. i. 1851, p. 234. 

t See Froriep's Neue Notizen, Bd. xii. loc. cit. supra. 

% See Muller's Archiv, 183/, p. 417- 

§ I have already called attention to this fact at the meeting of German 
naturalists at Gotha, as appears from the short notice in the Tagblatt der 
2Sten Versammlung deutscher Naturforscher und Aerzte, No. 3. p. 28. 



28 PARTHENOGENESIS IN SOME 

reproductive process just described by me in Soienobia trique- 
trella and lichenella. 

The two species of Sac-bearers just mentioned are not however 
the only representatives of the true Parthenogenesis ; an equally 
striking example of the virgin reproduction of a female insect is 
presented by Psyche Helix. Of this extremely remarkable moth 
we are at present only certainly acquainted with the female. In 
the caterpillar state it lives in a sac, which in its form resembles 
a sinistral snail-shell, to which similarity the specific name given 
by me to this Psyche also refers. 

The sac of Psyche Helix is nearly as large as a small pea 
(generally 2 lines Rhenish in height, and the same in breadth) ; 
it exhibits three and a half whorls (figs. 1-3), and consists of a 
firm whitish tissue, which is thickly and firmly coated externally 
with small particles of earth. The colour of the sac is usually 
earthy-grey, but in certain districts blackish or reddish-brown 
sacs occur; this is probably in connexion with the colour of 
the soil from which these Sac-bearers partly derive the material 
for their sacs. Here and there also individual cases occur with 
separate whorls (anfractibus devolutis). The uppermost and 
narrowest half-turn is always very indistinct, and generally ap- 
pears collapsed. At the place where the second whorl com- 
mences there is always a lateral opening (figs. 2, 3, & 6 a), the 
margins of which usually lie down and conceal the entrance 
to the cavity of the whorl*. When the caterpillar has evacu- 

* Besides Psyche Helix, there are some other insects, whose larvae, as case- 
bearers, manufacture sacs in the form of a snail-shell. In the genus Psyche 
itself there occurs another species, the caterpillars of which, like those of 
Psyche Helix, bear about with them a spirally-twisted sac. By the kindness 
of Herr Zeller of Glogau and Dr. Rosenhauer of Erlangen, I possess two 
earth -coloured, snail-like sacs with perfectly flat convolutions (figs. 15-1 7) * 
found in Sicily and Spain. They are nearly three times as large as the sacs 
of Psyche Helix, and from their different form and size belong to another spe- 
cies, to which I will give the provisional name of Psyche Planorbis. Both 
sacs, like those of Psyche Helix, are covered with fine grains of earth and sand 
cemented on them. Behind the uppermost and narrowest half-turn there is also 
a lateral aperture, which is due to an interruption in the walls of the sac taking 
place here (fig. 15 a). In the family of the Phryganidce also, larvee occur, 
which form a spirally-twisted domicile. The first notice of this was furnished 
by Shuttleworth (in the Mittheilungen der naturforschenden Gesellschoft in 
Bern, June 1843, p. 20), and as this is but little known, I will reproduce it 



SAC-BEARING LEPIDOPTERA. 29 

ated its faeces, it pushes them out of this aperture, when the 
edges of the latter rise a little. This lateral opening of the sac 

here literally. The passage in question rims as follows : — " Amongst the 
Mollusca collected by Blauner in Corsica, there was a considerable number of 
a shell, which was at first taken for an undescribed species of Valvata, and 
which appeared to be nearly allied, if not identical, with the Valvata arenifera 
of Lea (Observ. p. 114. tab. 15. figs. 36 a & b), from North America. The 
perfectly regular, spirally convoluted shell consists of a very fine transparent 
membrane, upon which very small grains of sand and stones are fixed with the 
greatest regularity. The circular orifice is closed by a very delicate, appa- 
rently spirally convoluted, membranous operculum. The general form, as well 
as the dimensions, remind one strikingly of the Valvata depressa, Pf. In all 
the individuals provided with an operculum, there was either the larva or the 
nympha of an insect, probably belonging to the genus Phryganea, which, bent 
into a half-spiral, lay singly in each shell. Under the microscope, the oper- 
cula exhibited, besides the spiral or regularly concentric structure above 
referred to, an excentric longitudinal opening running parallel to the inner 
margin. Specimens of the Valvata arenifera of Lea, which I have recently 
obtained from Vienna, exhibit precisely the same structure both of the shell 
and operculum. In Reaumur's Memoires pour servir a VHistoire des Insectes, 
torn. hi. p. 193. pi. 15, figs. 22-24, there is a short description and figure of a 
(spirally-convoluted) Phryganea-c&se (occurring in Switzerland). This species 
of Reaumur's, however, differs in every other particular from the species above 
described, and also appears to possess no operculum." The case last referred 
to by Shuttleworth belongs to Psyche Helix ; the other one, which resembles 
a Valvata, on the contrary, is a very different thing (see my figures 18-22), 
and is certainly produced by a Phryganidous insect. I saw several of the 
habitations of this insect in Bremi's collection at Zurich, partly collected in 
Corsica and partly on the Lake of Como. Bremi has given the name of 
Helicopsyche Shuttleworthi to the questionable Phryganidan from which 
these spiral cases are derived ; and many specimens of a similar smaller case 
have been since sent to him from a brook in Porto Rico, the inhabitant of 
which Bremi has named Helicopsyche minima. By the kindness of Hen Bremi 
I have obtained several specimens of both kinds, which are essentially different 
in their structure from the sacs of Psyche Helix. As regards their size, the 
diameter of the largest sacs of Helicopsyche Shuttleworthi is 2 lines (Rhenish), 
and of those of H. minima 1 line. A principal distinction between these Phry- 
ganidan domiciles and the spiral sacs of Psyche consists in the fact, that whilst 
in the case of Psyche Helix extremely fine grains of sand are stuck as a coating 
upon the outer surface of the white web of the sac-walls, in Helicopsyche the 
walls of the habitation are formed directly and solely of larger, polygonal par- 
ticles of sand, closely cemented together from within and without. The cater- 
pillars of Psyche also never close their sacs with au operculum. But that the 
Helicopsyche-sucs are really produced by a Phryganidous insect, I ascertained 
from the contents which I extracted from two cases of Helicopsyche minima 



30 PARTHENOGENESIS IN SOME 

is really due to an interruption, which the walls of the sac ex- 
hibit at this point in almost the whole of their transverse diameter. 
The body of the caterpillar is indeed also spirally curled (figs. 4 
and 7), but in its form and length it only corresponds with the 
lowermost whorl of the sac. In this way it would be impossible 
for the caterpillar to push its body up into the uppermost narrow 
whorl for the evacuation of its faeces. The female of Psyche 
Helix, like all females of Psyche, after completing the business 
of oviposition, quits its sac, which is firmly spun down by its 
anterior aperture, and for this purpose it makes use of the lateral 

still furnished with opercula. These consisted of a dried pupa, which in the 
form of the legs and of the long antennae, the four hairy rudiments of wings, 
and the two biting jaws, exactly resembled a Phryganidan. The description 
given by Lea of his Valvata arenifera (in his Observations on Najades and 
Descriptions of new species, vid. Transactions of the American Philosojihical 
Society, vol. iv. Philadelphia, 1834, p. 104. pi. 15. fig. 36 a, b. See my copies, 
figs. 23, 24) runs as follows : — " Testa orbiculata, convexa; anfractibus tribus, 
qui arenis agglutinatis operiuntur ; umbilico lato ; spira obtusa. Hab. Cum- 
berland River near Nashville. Length four-twentieths of an inch. Remarks. — 
This very curious and interesting species was among the freshwater shells so 
disinterestedly sent to me by the Lyceum of Natural History of New York, to 
be examined and inserted in this paper. It has the singular property of 
strengthening its whorls by the agglutination of particles of sand, &c, by 
which it is entirely covered, and in this character it resembles the Trochus 
agglutinans, Lam. (Trochus conchy liophorus, Authors). The apex, in all the 
specimens which I have had an opportunity of examining, is broken. The 
operculum was observed in two specimens sufficiently perfect to exhibit a 
striated horny structure." 

The sacs of Helicopsyche minima communicated to me by Bremi, agree 
almost perfectly with this shell of Valvata arenifera described and figured by 
Lea. Even the bronze-green colour is common to both of them. The pre- 
sence of an operculum is also in favour of the derivation of this habitation 
from a Phryganidous insect, as the Sac-bearers amongst the Lepidoptera form 
no operculum, but always spin down their sac by its lower aperture to foreign 
substances. Moreover, the opercula, of which I found several in my specimens 
of the sac of Helicopsyche minima, had also a striated appearance like those of 
Valvata arenifera. They were smaller than the aperture of the sac, and con- 
sequently only closed it imperfectly. On examining them with the micro- 
scope, I detected a fibrous structure in these opercula, arising from compara- 
tively coarse-spun threads, sticking close together; at the margins of these 
opercula single threads protruded, by which they were united with the mouth 
of the sac. In my specimens of the sacs of Helicopsyche Shuttleworthi I per- 
ceived no opercula; they had probably fallen off, or perhaps were not formed 
when these sacs were collected. 



SAC-BEARING LEPIDOPTERA. 31 

opening in the hinder whorls of the sac, although the animal 
with its empty, shrivelled body could easily force its way out 
through the uppermost narrow whorl, and through the narrow 
aperture at the apex of the sac. But there is probably another 
circumstance which prompts the caterpillar instinctively, whilst 
finishing and enlarging its sac, to introduce a lateral opening 
below the uppermost narrow whorl ; I mean the eventual per- 
mission of the act of copulation, which in this case, from the 
peculiar form of the sac, could only be effected through a low 
lateral aperture of this kind. 

This Sac-bearer was first mentioned by Reaumur*, but has 
since remained entirely unnoticed by entomologists. It is only 
very recently that greater attention has been given to these 
Heliciform caterpillar-sacs. My attention was first called to 
this Sac-bearer in Freiburg in the latter part of the summer of 
1849 by Von Hey den, to whom entomology is indebted for so 
many interesting discoveries. It was discovered by Von Heyden 
spun down on rocks on the Schlossberg near Freiburg, and sub- 
sequently the same animal was found on the Isteiner Klotz be- 
tween Freiburg and Basle f. This Sac-bearer was forwarded to 
me by Zeller from the neighbourhood of Glogau, and I received 
several living specimens, collected a couple of miles from Vienna, 
near Modling, through the kindness of Kollar, in whose com- 
pany I afterwards (in the year 1850) collected many specimens 
in the same locality. Dr. von Frantzius also brought me some 
specimens of this Sac-bearer from Meran. By Herrich-SchafTer's 
intervention, I obtained many of the same sacs from the district 
of Tegernheim near Ratisbon, and this Sac-bearer was also ob- 
served by Mann and Zeller in Sicily J. Besides the habitat 
given by Reaumur, Besancon and Dijon in France have recently 
been indicated by Bruand as localities for this Sac-bearer §. In 

* See Memoir es pour servir a I'Histoire des Insectes, torn. iii. parti, edit. 
12mo, p. 249. pi. 15. fig. 20-22, figures of the sac of Psyche Helix (sec the 
copies of these in my plate, figs. 10-12). 

f See Reutti's Uebersicht der Lepidopteren-Fauna des Grossherzogthums 
Baden, in the Beitrdge zur rheinischen Naturgeschichte, Heft 3. 1853, p. V.K 

% See my Bemerkungen iiber Psychiden, in the Jahresbericht der schlesiscken 
Gesellschaft fur vaterlandische Cultur iiber 1850, p. 87 (transl. Ent. Trans. 
new ser. vol. i.). 

§ See his Essai monographique sur la Tribu des Psychides, in the Memoir: s 



32 PARTHENOGENESIS IN SOME 

Bremi's collection at Zurich I saw specimens of this sac, which 
had been sent from Ticino and the Valais. By the kindness of 
Dr. Rosenhauer of Erlangen, I obtained a spiral sac, which was 
found near Malaga in Spain, and which, from its size, probably 
belongs to a species distinct from Psyche Helix. The form of 
this sac is exactly the same, but its breadth is 3 lines and its 
height 2f lines. 

The caterpillar of Psyche Helix selects various plants for its 
nourishment. On the Schlossberg near Freiburg it feeds upon 
Artemisia vulgaris. According to Zeller's testimony it also lives 
upon Anthyllis vuhieraria, Lotus corniculatus, and Gnaphalium 
arenarium. Kollar found his on Atriplex laciniata. Near Ratis- 
bon I observed these sac-bearing caterpillars feeding upon 
Alyssum montanum and Teucrium Chamcedrys. It is also stated 
by Bruand, that besides Cheiranthus odoratus and Scabiosa 
arvensis, this Sac-bearer was most frequently met with upon 
Teucrium Chamcedrys. Reutti fed these caterpillars with Lamium 
purpureum, and I myself supplied them with Lotus corniculatus 
and Hippocrepis comosa. These Sac-bearers are leaf-miners 
after the fashion of the caterpillars of Coleophora, pushing their 
bodies far in between the epidermic plates of the leaves, through 
a round hole which they gnaw in the latter, and devouring the 
chlorophyll all round them, during which process the sac re- 
mains outside sticking with its aperture to the opening in the 
epidermis. The leaves, and even the variegated flowers of the 
food-plants are in this way often completely decolorized by the 
Sac-bearers. The caterpillars of Psyche Helix are of a dirty 
white colour; the head, the legs, the three thoracic segments, 
and the extremity of the abdomen possess a hard, blackish- 
brown intesument. The constrictions of the thorax and also its 
median line are colourless (figs. 2, 4, 6 & 7). When taken out of 
the sac, the caterpillar, in creeping about, retains the same 
gentle spiral curvature of the body as when within the sac. 
When these Sac-bearers are full-grown, which is the case in 
the latter part of the summer, they quit their food-plants like 
the other caterpillars of the Psychiclce and seek a suitable place 
for their change to the pupa state. When they find stone walls 

de la Societed' Emulation du Doubs, Anne'e 1852, p. 74. pi. 2. fig. 48 6 (sac of 
Psyche Helix). 



SAC-BEARING LEP1DOPTERA. 33 

or rocks in their vicinity they creep high up on them, and spin 
down the lower aperture of their dwelling firmly. In passing 
through the process of moulting also, these caterpillars, like 
all other Sac-bearers, always spin down their habitations tem- 
porarily. The evolution of the moth takes place in the same 
year*. If after some time we examine the spun-down sac of a 

* This Sac-bearer, like the other Psychidce, is exposed to the attacks of 
Ichneumonidce. It is remarkable that the Ichneumonidous parasite of Psyche 
Helix is a Chalcis, whilst I have never yet reared a Chalcis from the caterpillars 
of the other Psychidce. This Chalcis, which was indicated to me by Kollar 
under the name of Chalcis nigra, does not, however, appear to occur very gene- 
rally. Reaumur obtained it from the sacs of Psyche Helix found in France, 
as appears from his notice, short as it is (see Mem. pour serv. a I'Hist. des Ins. 
torn. hi. p. 250); the sacs collected near Modling also furnished me with this 
Chalcis in abundance ; but on the other hand, from more than a hundred sacs 
which I had obtained from Tegernheim near Ratisbon, no Chalcis, and indeed 
no Ichneumon at all, escaped. The Chalcis always eats its way out at the side 
of the sac between the first and second whorls, and leaves a round hole corre- 
sponding with its size on the outside of the sac (fig. 1 b). This Chalcis (figs. 
13, 14) belongs, according to Nees von Esenbeck's Hymenopterorum Ichneu- 
monibus affinium Monographic, vol. ii. p. 27, to the species of the genus Chal- 
cis described in Sectio II. (abdominis petiolo brevissimo); its specific character 
may be diagnosed in the following manner : — nigra, pubescens, scutello in me- 
dio marginis dente obtuso, femoribus posticis subtus obsolete uuidentatis, tar- 
sis piceis. Long. lin. 1 — l£. The other Ichneumons reared by me from the 
caterpillars of Psychidce are as follow : — 

Campoplex difformis, Gr., from Fumea nitidella, Ochs. 

lsetus, Rtzb., from Fumea betulina, Zell. 

lugens, Rtzb., from Fumea nitidella and betulina. 

psilopterus, Gr., from Solenobia lichenella, Linn. 

Cryptus eborinus, Rtzb., from Fumea nitidella. 

spiralis, Gr., from Taheporia pseudobombycella, Ochs. 

Hemiteles albipennis, Rtzb., from Solenobia triquetrella, Fisch. v. R. 

areator, Gr., from Psyche calvella, Ochs. and Fumea nitidella. 

elongatus, Rtzb., from Talajporia pseudobombycella. 

gastroccelus, Rtzb., from Solenobia triquetrella and lichenella. 

imbecillus, Gr., from Fumea nitidella. 

leucomerus, Rtzb., from Solenobia triquetrella, Fisch. v. R. 

melanarius, Gr., from Solenobia triquetrella. 

similis, Gr., from Psyche calvella. 

tristator, Gr., from Fumea nitidella. 

1 nov. sp. from Fumea betulina. 

2 nov. sp. from Tala3poria pseudobombycella. 

Microgaster longicauda, Wesm., from Solenobia lichenella. 

Pezomachus agilis, Gr., from Psyche calvella. [Peaomachua 

D 



34 PARTHENOGENESIS IN SOME 

Psyche Helix during its period of pupation, we find the pupa in 
the lower whorl of the case, with its anterior extremity directed 
upwards, and its hinder extremity downwards towards the 
attached lower aperture. Between this and the extremity of the 
abdomen of the pupa, the shrivelled skin of the caterpillar stripped 
off in its last change of skin is always fixed, so that this cater- 
pillar, like all the caterpillars of the Psychida, turns itself round 
in the sac before the true pupation. In all the sacs of Psyche 
Helix in the pupa state, hitherto examined by me, of which I 
have had the opportunity of observing more than a hundred and 
fifty within seven years, I never found any but a female pupa. 
This is motionless, of a yellowish-brown colour, and with very 
indistinct segments ; it presents a body which is slightly dimi- 
nished in front, and gently curved in a spiral form corresponding 
with the lower spiral whorl of the sac (fig. 5). 

The wingless and almost footless female moth which is evolved 
from this pupa, also appears slightly curved in a spiral (figs. 8, 9). 
Its colour is grey, with a very slight brown tint on the back of 
the three thoracic segments. The anterior extremity of the body 
is somewhat narrowed ; the exantennate head, which is strongly 
bent downwards, exhibits very indistinct and quite abortive oral 
organs ; and on each side of it two dark pigment-spots are per- 
ceptible, which however contain no eye-facets. The abdomen 
is sparingly beset with white hairs. The varicose urinary vessels 
shine through the skin of the body here and there with a whitish- 
yellow colour, as does also the violet ventral chain of ganglia. 
The movements of these females of Psyche are extremely sluggish, 
and the six little feet of the three thoracic segments, which are in 



Pezomachus cursitans, Gr., from Psyche graminella, Ochs. 

geochares, Forst., from Fumea nitidella. 

pedestris, Gr,, from Psyche calvella and Fumea nitidella. 

1 nov. sp. from Psyche calvella. 

2 nov. sp. from Psyche calvella. 

Phygadeuon tenuipes, Gr., (?) from Fumea nitidella. 
Pimpla annulicornis, Rtzb., from Psyche graminella. 

examinator, Gr., from Psyche graminella, Fumea betulina and niti- 
della. 

scanica, Gr., from Psyche calvella and Fumea nitidella. 

Pteromalus Zelleri, Rtzb., from Fumea nitidella. 



SAC-BEARING LEPIDOPTERA. 3. r ) 

the form of very short conical processes, scarcely take any part in 
them. A dissection which I made of several of these animals, 
convinced me that I really had female insects before me ; the 
internal and external organization of their sexual organs being 
exactly the same as in other females of Psyche. The two sexual 
orifices presented themselves in all the individuals, as well as the 
copulative pouch and seminal receptacle, both of which of course 
were always empty. The eight ovarian tubes only contained a 
very few eggs. 

Like all other true species of Psyche these female moths de- 
posited their yellowish eggs in the empty pupa-case, which, in 
Psyche, always remains behind in the caterpillar-sac ; they then 
shrivelled up to a very small volume, when they generally left 
the sac by the above-mentioned lateral aperture and soon after- 
wards died. 

The unfertilized eggs, concealed in the pupa-case, are also 
developed in the same year. If a spun-down sac of Psyche 
Helix be opened in the latter part of the autumn or in winter, 
we always find from ten to four-and-twenty young, reddish-grey 
caterpillars in the interior of the pupa-case. On the empty 
colourless egg-shells, which may be found crushed between the 
caterpillars, the micropyle is distinctly recognizable under the 
microscope. 

After I had thus never detected any other mode of reproduc- 
tion but that by Parthenogenesis in Psyche Helix, it necessarily 
astonished me that other entomologists should have succeeded 
in obtaining the males of this species. On a closer examination, 
however, it appears doubtful whether the moths described as 
males of Psyche Helix really belong to this species. Thus the 
male of a Psyche helicinella was figured by Herrich-SchafTer, 
together with a sac of Psyche Helix*. The moth figured was 
discovered by Mann in Sicily : as an empty sac of Psyche Helix 
occurred in its vicinity, Mann supposed that the moth had escaped 
from this sac. Herrich-S charier himself, however, leaves it doubt- 
ful, whether this spiral sac really belonged to the moth figured 
by him, saying, " the sac (if really belonging thereto) is like a 
snail-shell, formed only of grains of sand, without portions of 

* See his Systematische Beschreibung der Schmetterlinge von Europa, Band 
ii. p. 21. figs. 108, 109. 

D 2 



36 PARTHENOGENESIS IN SOME 

plants." For this reason I have retained the name of Psyche 
Helix, which I gave to the female moths reared by me from the 
snail-like sacs, as it is not yet proved that the Psyche helicinella 
of Herrich-SchafFer actually belongs to my Psyche Helix. The 
same applies to the male moth described and figured by Bruand 
as Psyche helicinella*. Bruand describes as belonging to Psyche 
helicineUa, the female and sac-bearing caterpillar of my Psyche 
Helix, but says expressly, that he has never been able to rear this 
Sac- bearer to the evolution of the mothf. From this, there- 
fore, we have no certainty that the winged individuals of Psyche 
helicinella, taken in the open air by Bruand, are the males of my 
wingless female Psyche Helix. As the males of Psyche copulate 
with their females whilst concealed in the interior of the sac, and 
for this purpose push their abdomen into the hinder free aperture 
of the female sac, the male of Psyche Helix will also perform 
this action, and will therefore probably possess an abdomen 
curved to correspond with the convoluted sac of the female. No 
such curvature of the abdomen is perceptible in either of the 
males figured by Herrich-SchafFer and Bruand, from which my 
doubts above expressed gain still greater support. Further 
observations, therefore, are to be made as to the existence of the 
male individuals of Psyche Helix. Perhaps those two flat spiral 
sacs which I have previously described (p. 28 note*) as belonging 
to a distinct species of Psyche (Ps. Planorbis) may be produced 
by the caterpillar of the male Psyche Helix, which would be by 
no means very improbable, as the caterpillar-sacs of certain other 
Psychida differ in form and size according to the sexes. The 
most striking example of this kind is presented by Solenobia 

* See his Essai monographique, fyc. ut cit. supra, p. 73. pi. 2. fig. 48 a. 

t Upon this Bruand expresses himself (p. 74) in the following manner :— 
"Cette chenille est fort difficile a elever, et, pour ma part, apres trois essais 
successifs, j'ai renonce a obtenir le papillon en domesticite. II est probable 
que quelques circonstances atmospheriques (la rosee matinale, par exemple) 
sont necessaires a son eclosion. La chenille se nourrit tres-bien jusqu'au 
moment de sa transformation ; alors elle commence a errer ca et la dans le 
vase ou la boite qui la renferme, ennn elle se fixe aupres les parois .... puis 
rien n' arrive ; elle meurt miserablement." With me, the rearing of these Sac- 
bearers after they were nearly full-grown, to the evolution of the female, has 
not been attended with difficulty, in spacious airy breeding-cages, and with a 
constant supply of fresh food (Lotus corniculatus). 



SAC-BEARING LEPIDOPTERA. .37 

clathrella, Zell.* I also leave it undecided, whether that larger 
sac already mentioned by me (p. 32), which, except in its size, 
differed in nothing from the sacs of the female Psyche Helix, 
does not belong to a caterpillar, which might have become 
developed to a male individual of Psyche Helix f. 

* See Zeller's Beschreibung des m'dnnlichen und weiblichen Sackes dor Sole- 
nobia clathrella, in the Linneea Entomologica, Band vii. 1S52, p. 345. See 
also Fischer von Roslerstamm, Abbildungen zur Berichtigung und Erg'dnzvng 
der Schmetterlitigskunde, p. 84. taf. 38. 

f [May not the Psyche Planorbis and the larger heliciform-sac, both from 
Spain, be the male and female sacs of one species, and the mule sac of P. Helix 
be also Planorbis-like, but smaller than the Spanish specimens? — W. S. D.] 



38 



TRUE PARTHENOGENESIS IN THE HONEY-BEE. 

Whilst I was occupied with my task of establishing a Partheno- 
genesis in Psyche Helix, and Solenobia triquetrella and lichenella, 
I did not omit to bring within the limit of my investigations 
other insects also, of which the story went that the females were 
capable of independent reproduction in the virgin state without 
the assistance of a male individual. It was of importance to 
look carefully at the Honey-Bee, upon the reproduction of which 
the most extraordinary statements have been made at all times 
by the various Bee-keepers. Amongst these statements my 
attention had already long been turned to that remarkable faculty 
which was ascribed to certain Worker-Bees, and which was said 
to consist in their being able to lay eggs capable of development 
without copulation*. In the year 1851, therefore, I put myself 
in communication from Breslau with various Bee-keepers, and 
in this way became acquainted with the distinguished Apiarian 
Dzierzon, pastor at Carlsmarkt near Brieg in Silesia. By this 
Apiarian, who is gifted with an admirably acute power of ob- 
servation and free from prejudices, I was furnished, partly in 
letters and partly by word of mouth, with information upon 
the oeconomy of Bees and the most important phenomena of 
Bee-life, of a kind such as I could never have obtained from zoolo- 
gical and entomological works. What surprised me most in these 
communications, was the entirely new theory of reproduction 
which Dzierzon had established, with which he then made me 

* [Hunter, in his paper "On Bees," Phil. Trans. 1792, refers to this opinion, 
but had been unable to confirm it. " It is asserted by Rieni, that when a hive 
is deprived of a queen, labourers lay eggs."..." and Wilhelm says that it is 
the labourers only that lay drone-eggs." Hunter then quotes from Schirach : — 
"A young queen lately hatched was put into a hive, which had been previously 
ascertained to contain no drones, and whose queen was removed ; and yet the 
voung queen laid eggs." Upon which he remarks — " There is no mystery in 
this ; but did they hatch ? " The definite reply to this question, and the nature 
of the product of the virgin-egg, are amongst the valuable facts in the present 
work.— R. O.] 



PARTHENOGENESIS IN THE HONEY-BEE. 39 

acquainted, and by which all the phenomena relating to the 
process of reproduction in the Bees, which so often border upon 
the marvellous, may be completely explained. 

One of these remarkable phaenomena is the property just 
referred to possessed by some Worker-Bees of laying eggs capable 
of development, a property which is denied by no observant Bee- 
keeper, but could not hitherto be satisfactorily explained in any 
way. The dissection of the Worker-Bees had shown, that they 
possess undeveloped ovaries, that the seminal receptacle is only 
imperfectly developed in them, and that, by reason of the abor- 
tion of their copulative organs, they are by no means in a condi- 
tion to copulate with a Drone (a male bee) and allow themselves to 
be fertilized by him. But whence then should this reproductive 
faculty of certain Worker-Bees arise ? At first I attempted to 
bring this reproductive power into connexion with the Alterna- 
tion of Generations, and expressed the supposition* that similar 
circumstances might occur amongst the Bees as amongst the 
Aphides, and that consequently amongst the Bees individuals 
were produced at certain times, which, as nurse-like creatures, 
could produce brood, without fertilization. But if nurses 
really did occur in the Bee-colonies, these must have been 
recognizable by careful dissection, as instead of ovaries they 
would contain germ-stocks, and no trace of a seminal receptacle. 
I at the same time expressed the wish that I might soon have 
an opportunity given to me of submitting Bees, which had been 
ascertained to be fertile workers, to a careful dissection and 
microscopic examination, in order to decide whether or no they 
really were nurses. 

But when I became acquainted with Dzierzon's theory of the 
propagation of the Bees, and constantly grew more and more 
convinced of its correctness, it was evident to me that we cannot 
speak of a nurse-formation amongst the Bees. To inform my- 
self as completely as possible about this theory, I went myself 
to Carlsmarkt and held a conference with Dzierzon on the 26th 
July 1851, in which I opposed all possible doubts to his theory 

* See my Bemerkungen iiber die Lebensweise md den HoushaU der Bienen, 
in the Jahresbericht der schlesischen Gesellschaff fur vaterWndische Cultur im 
Jahre 1851, p. 48. 



40 PARTHENOGENESIS 

of reproduction ; but these were constantly set aside by him, and 
with such convincing reasons, which could be brought into 
accordance both with the anatomical relations of the Bees and 
with the physiological laws of insect and animal life in general, 
that at last I could no longer hesitate in admitting the correctness 
of Dzierzon's theory of reproduction. 

Dzierzon expressed his views upon the reproduction of Bees 
in the year 1845 in the Bienenzeitung of Eichstadt*. but without 
particularly emphasising the most important details of his theory, 
and without elevating it into a peculiar theory. I consider it 
necessary to reproduce the views expressed by Dzierzon in that 
Journal, word for word. They run as follows: — 

" Presupposing, what will be referred to and proved in the 
following Numbers, that the Queen (female bee) to become good 
for anything must be fertilized by a Drone (male bee), and that 
the copulation takes place in the air, I express the conviction, 
from which all phaenomena and mysteries may be perfectly 
explained, that the drone-eggs do not require fecundation ; but 
that the cooperation of the Drones is absolutely necessary when 
Worker-Bees are to be produced. Whilst in the higher animals 
the male is the perfect and ruling creature— the bull keeps to- 
gether and as it w r ere governs the herd of cattle, and the cock 
does the same by the hens — the reverse of this takes place in 
Insects. In the Wasps, Hornets, Humble-Bees, Ants, and espe- 
cially in the Bees, the perfect female forms the central point and 
holds the swarm together. As even the drones are subordinated 
to her, they are also in themselves altogether imperfect creatures, 
for the production of which so many forces and conditions are 
not necessary even on the part of nature as for the production 
of the queen, and, what is the same thing, of the workers. (The 
ancients even appear to have indicated this by the denomination 
Fucus.) The truth of this assertion appears at once from the 
fact, that as everything that is capable of the more difficult and 
greater effect may also produce the easier and smaller one, so 
every stock, which is in a condition to produce worker-bees, may 
also produce drones, when suitable cells are not wanting in the 
nest; but not inversely. In copulation the ovaries are not 

* See Bienenzeitung, herausgegeben von Dr. C. Burth und A. Schmid in 
Eichstadt. Jahrgang i. 1845, p. 113. 



IN THE HONEY-BEE. 41 

fecundated, but the seminal receptacle, that little vesicle or knot 
which in the young queen is filled with a watery moisture, is 
saturated with semen, after which it is more clearly distinguish- 
able from its white colour. The activity of the ovary in the 
normal state only commences after copulation, but is not neces- 
sarily caused thereby ; hence many unfecundated queens lay no 
eggs at all, whilst others lay drone- eggs; and even workers do 
the latter, although, from their want of a seminal receptacle, I 
regard them as quite incapable of copulation. I am convinced 
that such eggs are sufficient for the production of drones, whilst 
the egg from which a queen or a worker is to be developed must 
come in contact with the filled seminal receptacle. This is cer- 
tainly only a hypothesis, and will probably remain so, but one to 
which every close observer will be no more able to refuse his 
assent, than the hypothesis of Copernicus, that the earth turns 
round upon its axis ; for all the mysterious phenomena in the 
commonwealth of the Bees are very simply explained by it." 

In a separate Bee-book, Dzierzon subsequently summed up 
his views upon the reproduction of Bees as a regular theory in 
the following manner * : — 

" Therefore, and this must be well borne in mind, in the 
copulation of the queen, the ovary is not impregnated, but this 
vesicle or seminal receptacle is penetrated or filled by the male 
semen. By this, much, nay all of what was enigmatical is 
solved, — especially how the queen can lay fertile eggs in the early 
spring, when there are no males in the hive. The supply of 
semen received during copulation is sufficient for her whole life. 
The copulation takes place once for all. The queen then never 
flies out again, except when the whole colony removes. When 
she has begun to lay, we may, without scruple, cut off her 
wings; she will still remain fertile until her death. But in her 
youth, every queen must have flown out at least once, because 
the fertilization only takes place in the air; therefore no queen, 
which has been lame in her wings from birth, can ever be per- 

* Theorie und Praxis des neuen Bienenfreundes, oder neue Art der Bienen- 
zucht mit dem giinstigsten Erfolge angewendet und dargestellt von Dzierzon, 
2 aufl. (without place of printing) 1849, p. 10(5. Dzierzon expressed himself' 
in exactly the same way in a Supplement to the Theorie und Pnuis, published 
in 1852, p. 4 et seq. 



42 PARTHENOGENESIS 

fectly fertile : I say, perfectly fertile, or capable of producing 
both sexes. For, to lay drone-eggs, according to my experience, 
requires no fecundation at all. This is exactly the new and 
peculiar point in my theory, which I at first only ventured to 
put forward as a hypothesis, but which has since been com- 
pletely confirmed. Three young queens with imperfect wings 
have occurred during the past summer, and these, although, 
from the imperfection of their wings, they could evidently never 
have taken the fertilizing flight, and also on dissection proved 
to be unfecundated, nevertheless laid drone-eggs*."— " By this, 
all the mysteries which we have hitherto vainly endeavoured to 
unriddle, are completely solved. In the first place the enigma : 
Why is it that many mothers— they may be either queens or 
workers in their form — are only capable of propagating the 
male sex or drones ? Because the former are either unfecun- 
dated, or their fertility is exhausted ; the latter, on the other 
hand, are incapable of fertilization." 

" For I am firmly convinced that the egg-laying worker-bees, 
which occur abnormally, are, from the want of a seminal recep- 
tacle, just as little capable of being fertilized, as the young 
queens from the want of sound wings. Moreover there is cer- 
tainly no doubt, that by the peculiar tone of her wings the 
queen allures the drones to her, and disposes them to copulation, 
of which a worker is of course incapable. In the second place, 
the before-mentioned power of the fertile queen to lay worker- 
and drone-eggs at pleasure, is rendered very easy of explanation 
by the fact, that the drone-eggs require no impregnation, but 
bring the germ of life with them out of the ovary ; whilst other- 
wise it would be inexplicable and incredible. Thus, as it has 
already been shown that the ovaries are not impregnated, but 
that the seminal receptacle is filled, during copulation, the queen 
has it in her power to deposit an egg just as it comes from the 
ovary and as the unf ecundate d mothers lay it ; or by the action 
of the seminal reeeptacle, past which it must glide, to invest it 

* [Here Hunter would perhaps have repeated his question, " But did they 
hatch?" The particulars of the experiment by which Dzierzon knew that 
drones came out of these eggs are not detailed ; the fact, however, is established 
by the observations of Siebold and Leuckart, given in a subsequent part of the 
work.— R. O.] 



IN THE HONEY-BEE. 43 

with a higher degree, a higher potency of fertility, and awaken 
in it the germ of a more perfect being, namely a queen or a 
worker-bee. This of course she does instinctively, induced by 
the width of the cell to be furnished/' — " For the production of 
females in the bee-hive, therefore, more conditions and forces 
are necessary than for the production of males or drones. Every 
mother which is capable of producing worker-brood, can also 
lay drone-eggs, but not inversely." 

As was to be expected, these views upon the reproduction of 
Bees called forth the most lively contradictions amongst the Bee- 
keepers ; they were attacked with the most violent polemics in 
the Bee-journal above mentioned, at the same time however that 
most of the opponents, being destitute of any knowledge of the 
anatomical structure of Bees, and of any insight into the phy- 
siological import of the sexual functions in Insects, laid them- 
selves open so miserably, that it must have been an easy matter 
for Dzierzon to silence them; but as it was almost entirely 
dilettanti speaking to dilettanti, the dispute never came to an 
end, the most incorrect, extraordinary and absurd assertions 
upon the copulation, fecundation and oviposition of the Bees, &c. 
being put forward in sober earnest as established truths, without 
its being observed how completely such views, devised in the 
fancy of a Bee-keeper, were destitute of anything like scientific 
proof. Hence it was possible that, simultaneously with the 
theory set up by Dzierzon, which its originator sought to sup- 
port by important new evidence from time to time in the 
Bienenzeitung, questions for investigation and reply were again 
and again propounded in that Journal, upon which we must 
have been long perfectly clear, since the most important points 
in the reproduction of the Bees had been elucidated by Dzier- 
zon's theory. 

Thus in the different years of the Bienenzeitung up to the 
most recent time, we may find the following questions put for- 
ward as not satisfactorily answered, and the following points 
referred to as doubtful by various Bee-keepers : namely, whether 
the drones are really the male Bees ; whether the drones might 
not have the care of the hatching of the eggs; whether the 
drones are not truly abortions ; whether there are not also male 
worker-bees; whether the queen is not perhaps fertilized by 



44 PARTHENOGENESIS 

caressing or by mere agitation ; whether the copulation between 
the queen and a drone does not after all take place in the bee- 
hive, and more of the same kind. 

In opposition to these variously contradictory questions, I, 
as Vice-president of the third meeting of German Bee-keepers, 
held on the 2nd June, 1852, at Brieg in Silesia*, gave an 
exposition of the anatomical relations of the three kinds of Bees, 
the drones, the queen, and the workers, and called upon the 
Bee-keepers present to express their objections and doubts 
against the particular points of the theory established by Dzier- 
zon. This was done on several sides ; Dzierzon, who was present 
as President of the Society, defended his assertions with the 
means which his abundant observations, conceived with a correct 
understanding, furnished to his hand, whilst I came to his assist- 
ance with my observations made with the dissecting needle and 
the microscope, whenever reference was made to the different 
anatomical relations and the signification of the internal and 
external sexual organs of the Bees. 

Although the majority of the Apiarians did not so quickly 
drop their preconceived notions and incorrect views as to the 
oeconomy, and especially the reproduction, of the Bees, yet a 
constantly increasing number of voices was gradually raised in 
the Bienenzeitung to confirm the correctness of individual points 
in the theory of reproduction put forward by Dzierzon. People 
began to interest themselves in the anatomical structure of the 
Bees and of insects in general; they took notice of the know- 
ledge obtained in recent times by the microscope, by which a 
clearer view of the function of the male seminal fluid in the in- 
terior of female insects had been gained. To strip everything 
doubtful from those assertions in Dzierzon's theory which still 
had too much of the garb of a hypothesis about them, and allow 
them to appear as naked truths, those Apiarians, whose sole 
object was to get at the truth, took care that various individual 
Bees, the exact examination of whose condition might furnish 
the right explanation of different doubtful points in Dzierzon's 
theor}^, were handed over to practised entomotomists for a dis- 
section and opinion. In this way this theory constantly gained 
in firmness and form, and became strengthened in such a 
* See the Bienenzeitung, Adder Jahrgang, 1852, p. 117- 



IN THE HONEY-BEE. 4 ."> 

manner that it may now claim to have taken root in the soil of 
science, there to await a further development. Great merit, in 
regard to the recognition of Dzierzon's theory, is due to Baron 
von Berlepsch of Seebach, near Langensalza in Thuringia, as that 
intelligent and experienced Apiarian neither shunned sacrifices, 
time or trouble to obtain the most important information upon 
the hotly contested questions relating to the reproduction of Bees 
from his numerous Bee-colonies, which are extremely well arranged 
for observation. In a series of Apistical letters Berlepsch* has 
given a systematic exposition of the new theory of the reproduction 
of the Bees, and supplied the individual positions with proofs sup- 
ported upon the most arduous experiments, by which he has 
shown himself to be a distinguished observer and acute naturalist. 
It must also be mentioned that Dzierzon deserves to be cele- 
brated as making an aera not only in the theory, but also in the 
practice of Bee-keeping. He has, namely, given the Bee-hive an 
arrangement, by which it becomes possible for the Bee-keeper 
not only to follow the observation of the individual Bee-colonies 
and to check the proceedings of their individual members or of 
the foreign intruders in the most exact and certain manner, but 
also to control and guide the entire ceconomy of the indi- 
vidual hives from all sides. He hit upon the happy idea of 
causing the Bees to build their combs from transverse sticks 
placed loosely behind one another in the upper space of the 
bee-hive, by which he was enabled as often as he pleased to 
examine the whole of the combs in a hive one after the other, 
the interior of the hive being rendered accessible by taking 
away a moveable back or front wall, — as by this arrangement 
each individual comb, clinging from beneath to the loose trans- 
verse stick, can be taken out with this, examined on both sides, 
and again suspended in its place without injury. By the help of 
this ingenious arrangement f it had become possible for Dzierzon 

* These Apistical letters are published in the Eichstadt Bienenzeitung for 
the years 1853 and 1854, and form an extremely important document for our 
knowledge of the history of reproduction in the Bees and Insects in general. 

f As the lateral adhesion of the combs built down from the sticks frequently 
rendered their removal difficult, Berlepsch tried to avoid this inconvenience in 
a very ingenious way, by suspending in his hives, instead of the sticks, small 
quadrangular frames, the vacuity of which the Bees till up with their comb, by 



46 PARTHENOGENESIS 

not merely to trace what went on in a bee-hive from clay to day, 
or from hour to hour, — he could even convince himself most 
exactly, with his own eyes, at any time, as to what was taking 
place in every individual cell of the different combs in his hives. 
He was also enabled in this way to procure a knowledge of all 
the proceedings of the workers in the interior of the hive between 
the combs, and also to witness the doings of the queen bee. 
These were all advantages which even the celebrated hives with 
glass walls could not in the least present, as these latter bee- 
hives only permitted the surface of a single comb which was 
turned towards the glass to be inspected, but otherwise allowed 
but a very small and extremely imperfect insight into the inte- 
rior of a colony of Bees. 

Dzierzon could give the most exact account of the condition 
of his bee-hives. He knew the number and kind of the cells 
which were daily or hourly supplied with eggs by the queen ; 
he knew in what time the larvae in the eggs laid arrived at their 
exclusion ; he was enabled to observe the gradual growth of the 
larva; he could exactly ascertain what kind of food was fur- 
nished to this or that larva by the workers ; he could acquire 
the most positive information as to the time of pupation of a bee- 
larva, as to the period of the escape of the Bee from the covered 
cell, and as to the number and nature of the queen's cells; in 
this way he was always informed in what condition the queen 
governing a bee-hive was ; he could detect every disturbance, 
every irregularity, which, induced by multifarious circumstances, 
easily occurs in the well-ordered oeconomy of a hive, as quickly 
as its cause. 

What advantages this must have afforded to an Apiarian 
endowed with such an acute and unprejudiced power of obser- 
vation as Dzierzon, may be easily imagined. By this agency 
the most important and instructive information regarding the 
proceedings of a Bee-colony might flow in upon that acute 
observer, and it could not but happen that at last the ex- 
tremely remarkable and concealed process of the reproduction 
of the Bees would be correctly penetrated by the eye of man. 

which the removal and suspension of the combs are greatly facilitated, and 
altogether such a convenient arrangement is given to the Dzierzon hive, that 
nothing more remains to be desired. 



IN THE HONEY-BEE. 47 

But even for practice the Dzierzon bee-hives were of the 
greatest importance, for Dzierzon could know exactly, at any 
time, and of any one of his bee-hives, how strongly it was 
peopled, how industrious its inhabitants were, and what they 
were occupied with. He could always inform himself whether the 
number of workers was in proportion to that of the brood pro- 
duced by the queen, whether the number or presence of drone- 
larvae was or was not useful to the hive, whether the necessary 
store of food was present, &c. With all this, the intelligent Bee- 
keeper and possessor of Dzierzon hives, by the aid of which 
a complete insight into the state of each household of Bees 
might be attained, could exercise a directing and correcting 
action, by adding the wanting number of necessary workers to 
a hive which was poor in workers, or taking away some of the 
combs filled with eggs and brood from another scantily-peopled 
hive, so as to lighten its work, and hanging them in an abun- 
dantly-peopled hive for further care. The careful Bee-keeper 
now knew from what hives he had to remove the combs filled 
with drone-larvae which were either unnecessary or dangerous ; 
he was enabled to save a hive, the inhabitants of which, although 
otherwise industrious, threatened to become demoralized by the 
loss of their queen, from this dangerous state of anarchy, by 
taking care to replace this loss, where the Bees themselves 
omitted to do so. In short, with the assistance of Dzierzon's 
hives, an experienced and careful Bee-keeper may go to work 
like an intelligent gardener, who, by cutting away the unneces- 
sary shoots, and attending properly to the bud-bearing twigs, 
prepares and supports his trees for the production of a rich 
harvest of fruit*. 

* Although it is several years since Dzierzon gave his " New Theory and 
Practice of Bee-keeping" to the knowledge and use of the public through the 
medium of the press, the advances made by Dzierzon in Bee-keeping have 
only been able to make their way slowly and gradually in the circle of Bee- 
keepers ; nay, it took still longer before the assertions of Dzierzon relating 
to the reproduction of the Bees passed out of this circle to reach the ears of a 
physiologist and naturalist. For this, Dzierzon himself is to blame ; this 
Apiarian, otherwise so practical, hesitated to give his manuscript upon " Theory 
and Practice" to a respectable bookseller for publication, but preferred making 
known his inventions and discoveries in an extremely unpractical way, by 
allowing his Nene Theorie and Praxis to appear at first as published by him- 



48 PARTHENOGENESIS 

In turning to the more exact exposition of Dzierzon's theory 
of the reproduction of Bees, I give prominence to the most im- 
portant points in the history of their propagation, upon the 
establishment of which Dzierzon must have laid particular 
stress, as a number of the proceedings in a bee-hive relating to 
reproduction can only find their correct explanation and elucida- 
dation if we maintain, that the young unfe emulated queen never 
copulates in the bee-hive, but always outside this, high up in the 
air. I pass over the lively dispute which has been carried on 
amongst Bee-keepers from time immemorial for the defence or 
rejection of this point, and only refer to the fact that a queen 
has never been surprised in the act of copulation within the 
bee-hive by any Apiarian who has obtained an insight into the 
interior of a hive by the employment of Dzierzon's hives. The 
drones, as long as they remain in the hive, are always extremely 
sluggish insects, which are not even roused from their quietude 
and phlegm by the proximity of a queen desirous of copulation ; 
on the other hand, when a warm, clear and still day has allured 
them out into the open air, the sexual and copulative impulse 

self, and afterwards disposing of it to a private individual living in a village in 
Silesia for further distribution. Von Berlepsch justly complains of such a 
proceeding (in the extra Supplement to No. 21 of the Eichstadt Bienenzeitung , 
1852), as he, and with him many other Apiarians, were prevented by this 
awkward and troublesome arrangement from an early adoption of the true 
Dzierzon method of Bee-keeping; for (as Berlepsch expresses himself upon the 
Dzierzon hives) the invention of being able to take out the individual combs 
suspended from little sticks, is undoubtedly the most practically important 
one that has ever been made in Bee-keeping, and one which must necessarily 
reform, that is to say, antiquate all previous methods, and to which alone 
Dzierzon is indebted for the excellence of his breeds, and the almost complete 
revelation of the natural history of Bees, their mode of life and of working. 
After Dzierzon had sold his intellectual property into strange hands, which 
withheld the most important part of his method, the right construction of the 
true Dzierzon hives, from the public, he made another attempt to bring his 
" Theory and Practice of Bee-keeping " into general notice, by printing in the 
year 1854 the Bienenfreund aus Schlesien, a monthly journal of instruction 
and entertainment for lovers of nature in general, and Bee-keepers in par- 
ticular. Of this journal (published by Ad. Bander in Brieg) twenty-five 
numbers have appeared up to this time ; but I fear that, from its inconvenient 
form, and the somewhat diffuse style of the text, this means selected by 
Dzierzon is not adapted to make the public acquainted and familiar with the 
real essence of his theory and practice. 



IN THE HONEY-BEE. 49 

is awakened in the highest degree in these otherwise so sluggish 
drones. They rove through the genial air high over their hives 
with a loud humming to attract the attention of a queen, who 
would be impelled to take her wedding-flight by the same 
favourable weather. At any rate, very few of the many thousand 
drones attain the longed-for happiness of being selected and 
accepted by a queen for a husband, it being well known that 
the number of female Bees is very small in proportion to the 
great number of male individuals. But by means of this dispro- 
portion, the few female Bees, on taking their wedding-flight, are 
always sure of attaining their object, as from the number of 
drones roving through the air with the same intent, it will not be 
difficult for a queen to make choice of an agreeable consort. 

That the copulation of the Bees takes place in the open air, is 
certainly nothing remarkable, as we see so many other insects 
perform the act of copulation whilst flying freely about in the 
air. It is true that the copulative act is very quickly completed 
by the Bees, and this is proper to all those insects in general, 
which, with the Bees, belong to the order Hymenoptera ; whilst 
the males and females of insects of other orders usually remain 
for days closely united in copulation. For this reason it is one 
of the rarest events for even the most observant entomologist to 
surprise a pair of Hymenoptera in flagranti*. The Bee-keepers 
therefore must not be surprised that the act of copulation in 
Bees has hitherto been so little observed. However, it has acci- 
dentally been seen now and then by human eyes, when a pair of 
bees, united in the act of copulation, dashed down upon the 
earth from the upper regions of the air. Such isolated observa- 

* This is the reason why we find so many individual females or males 
placed as separate species in no other order of the class of Insects as in the 
Hymenoptera ; as in these insects the male and female individuals are often 
quite differently coloured and marked, and as no trouble has been taken with 
the rearing of them, as has been done with the Lepidoptera, it has hitherto 
been impossible with many of these Hymenoptera to discover the sexes 
belonging to the same species. Gravenhorst is therefore to be excused if he 
has established a quantity of species of Ichneumons (in his Ichneumonolo<ji<i 
Buropcea) which only consist of males or females. This certainly did not 
happen from that desire which is carried so much too far by many entomo- 
logists, of having the fame of giving a name to species which are new, but not 
founded in nature. 

E 



50 PARTHENOGENESIS 

tions, information upon which has also been given in the 
Bienenzeitung*, are certainly sufficient evidence that the Bees 
copulate outside the hive. 

A still more convincing proof of the occurrence of this act 
of copulation in the open air is furnished by the appearance 
and behaviour of the fertilized queen on her return from her 
wedding-flight. The completion of the coitus of such a queen 
may betray itself even externally ; not only does the external 
orifice of the sexual apparatus, which was kept closed before 
the wedding-flight, stand open, but the torn male copulative 
organs remain sticking in the vagina, and partly protrude from 
it. In order to determine with certainty from its nature what 
this foreign body, which had often been detected f in the 
vagina of a queen on her return from the wedding-flight, really 
w T as, Baron von Berlepsch forwarded to me for careful exami- 
nation, on the 21st July 1853, one of these queens, from the 
gaping sexual orifice of which definitely formed parts pro- 
truded %' The results with which the exact anatomical and 
microscopical examination of this queen has furnished me, have 
been given by me in the Bienenzeitung ^. By this analysis I 

* See Bienenzeitung, 1845, p. 38 ; 1852, p. 188 ; 1853, pp. 108 & 174. 

t Bienenzeitung, 1846, p. 95, and 1853, pp.43, 107 & 120. 

% The letter from Von Berlepsch, which accompanied this queen, contained, 
amongst other things, the following notes : — " Uninterruptedly occupied in 
clearing up the natural history of the Honey- Bee, that is to say, in bringing 
it to final conclusions, I succeeded, to-day, in impaling upon a pin, a queen 
which had flown out to copulate, just as she was about to re-enter the hive. 
The signs of copulation stand far out. In taking the liberty of sending you 
this carcase, I have to beg that you will have the kindness to settle by dissec- 
tion, — 1, if any, and what, parts of the drone occur in the royal vulva; and 
2, what is the condition of the seminal receptacle. If there be parts of the 
drone in the vulva, people will at last admit that the drones are the males, 
that the copulation takes place outside the hive, and that it is absurd to 
describe the drones as abortions, and seek the males amongst the worker- 
bees. Moreover, if you find the seminal receptacle filled with semen, Dzier- 
zon's hypothesis, according to which the ovary is not fertilized but the 
seminal receptacle filled with male drone-semen by copulation, is raised into 
evidence.'* 

§ See Bienenzeitung, 1854, No. 20. p. 227, Zergliederung einer vom Begat- 
tungsjluge heimgekehrten Bienenkonigin. Ein Sendschreiben an Herrn August 
von Berlepscli in Seebach. I have at the same time made use of this letter to 
explain to the Bee-keepers the anatomical conditions of the sexual organs of 



IN THE HONEY-BEE. 51 

was able to establish, that those definitely-formed parts in the 
vagina of the queen were nothing but the torn copulative organs 
of a male bee (drone). An intimate union of the two sexes of 
Bees must therefore have taken place here. The remaining 

the Bees, so that they might be at last convinced that the import of the drones, 
queen, and workers in a colony of Bees could only be rightly estimated by 
taking these conditions into consideration. That this was not superfluous, 
was shown me by the thanks, repeatedly expressed in the Bienenzeitung, with 
which my instruction was received by many friends of Bee-keeping. I thought 
it my duty also to render this service to the Apiarians, when I remembered 
what has been made known up to the present day as to the various erroneous 
opinions asserted by Bee-keepers with regard to the history of reproduction in 
the Bees (see supra, p. 2). To show into what wrong paths those Bee-keepers, 
who, entirely mistaking the objects laid before them by nature, only wish to 
pass off their own peculiar opinions, have got, I quote here literally from 
Magerstedt's Pratkisches Bienenvater (oder Anleitung zur Kenntniss unci Be- 
handlung der Bienen, 1842, p. 68) what he teaches as the natural history of 
Bees : — " The queen is the mother of all the worker-bees. Of these the greater 
number are of the male, the smaller number of the female sex. She lays the 
eggs of both kinds in the small narrow cells of the building. The care of the 
brood is the duty both of the male and female worker-bees, but at the same 
time they are assisted, for the furtherance of the work, by the sexless drones, 
and for this reason the number of the drones is greatest at the time when the 
most brood occurs. Their business is especially to warm the brood, and to 
elevate the temperature of the hive during the time when the workers are 
occupied out of doors. When, with a deficiency of nourishment and a diminu- 
tion of the business of taking care of the brood, their presence is no longer 
necessary, they are expelled. The queen, however, does not copulate. Her 
first fertilizing flight agitates her ovary, and by this means she becomes capable 
of laying fertile eggs." This book, tainted with such gross errors heaped one 
upon another, has recently made its appearance in a third edition. Von 
Berlepsch has assured me that he sent its author my letter, in order that he 
might change his opinion. But now, in this third edition, which appeared 
in 1856, we may read at p. 181 : — " The queen is the mother of all the worker- 
bees ; a greater number of the workers is of the male than of the female sex. 
Nature has distinguished both sexes externally. The queen is rendered 
capable of reproduction, not by copulation, but by the agitation of her ovary, 
and by its actions during the fertilizing flight, which is to be repeated several 
times. The female bees are also rendered capable of laying eggs by flying 
out, and by the agitation of their ovaries thus produced. From the eggs laid 
by the female bees, drones are produced, and these being perfectly asexual, 
do not cooperate in the business of reproduction, but in the care of the brood." 
And also at p. 2/9 : — " Certainly they (the drones) are not necessary for the 
fertilization (of the queen)." What shall we say to such a complete ignoring 
of the truth ? 

E 2 



52 PARTHENOGENESIS 

behind of torn portions of the male sexual organs in the interior of 
the female vagina, is, however, a circumstance which occurs not 
unfrequently in other insects, especially in Beetles, With this 
condition of the external sexual organs of the queen examined 
by me, the state of the internal generative organs also agreed 
exactly, for the seminal receptacle (seminal vesicle), which is 
empty in all virgin female insects, was in this queen filled to 
overflowing with spermatozoids (seminal filaments)*. This 
queen therefore had returned to her hive certainly fertilized, and 
would have possessed the power for a long time of effecting the 

* [The experiment by which Hunter distinguished the seminal-sac from the 
poison-sac in the complex female apparatus of the Queen-bee is ingenious and 
characteristic : " To ascertain which was the poison, I dipped points of needles 
into both (bags), and pricked the back of the hand ; and those punctures that 
had the fluid from the first-described bag in them grew sore and inflamed, 
while the others did not."— Phil. Trans. 1792, p. 190. 

He applied this anatomical knowledge to explain the impregnation of insects, 
as follows : — " Insects, respecting the males, are of two kinds : one, where the 
male lives through the winter as well as the female ; and the other where 
every male of that species dies before the winter comes on ; among which may 
be considered, as a third, those where both male and female die in the same 
year. Of the first I shall only give the common Fly as an instance ; of the 
second I shall just mention all of the Bee tribe; and the third may be illus- 
trated in the Silk-worm. The mode of impregnation, in the first, is its being 
continued uninterruptedly through the whole period of laying eggs ; while in 
the second, the copulation is in store ; and in the third, the female lays up 
by the copulation a store of semen, although the male is alive." — Ibid. p. 185. 

Hunter then proceeds to detail a series of experiments made to determine 
the influence of the contents of the spermatheca of the female Silk-moth 
upon the eggs, " which experiments," he says, " may be applied to the Bee, 
and many other insects." Of these experiments it will suffice to cite the 
following as illustrating his knowledge of that part of the mechanism of the 
female organs in the Moth and Bee on which so much of the important facts 
in the present work depends : — 

" Experiment II. — I took a female Moth, as soon as she had escaped from 
the pod, and kept her on a card till she began to lay. I then took females 
that were fully impregnated before they began to lay, and dissected out that 
bag which I supposed to be the receptacle of the male semen ; and, wetting a 
camel-hair pencil with this matter, covered the ova as soon as they passed out 
of the vagina. These ova were laid carefully on the clean card, and kept till 
the ensuing season, when they all hatched at the same time with those natu- 
rally impregnated. This proves that this bag is the receptacle for the semen, 
and it gradually decreases as the eggs are laid."— Phil. Trans. 1792, p. 188.— 
R. O.] 



IN THE HONEY-BEE. 53 

necessary fertilization of the eggs during oviposition with this 
supply of male semen. 

As in the act of copulation of the Bees, the penis of a drone 
is completely protruded outwards, and as no particular muscular 
apparatus exists for the extrusion of the penis, the circumstance 
that the drones only copulate in flight has an important signifi- 
cation, to which Leuckart* has already called attention; during 
the movement of the wings, the different air-sacs of the tracheal 
system of the drone are filled with air, by which means these can 
act by pressure in the interior of the body of the bee, upon the 
neighbouring penis which is to be protruded. 

After this single fecundation, a queen- bee can for a long time 
lay male or female eggs at will; for by the filling of her seminal 
receptacle with male semen she has acquired the power of pro- 
ducing female eggs, whilst before copulation and with an empty 
seminal capsule, and therefore in the virgin state, she can only 
lay male eggs. The second and most important point of the 
new theory of the reproduction of Bees, is the proposition esta- 
blished by Dzierzon, that, — All eggs which come to maturity in 
the two ovaries of a queen-bee are only of one and the same kind, 
which, when they are laid without coming in contact with the 
male semen, become developed into male Bees, but, on the contrary, 
when they are fertilized by male semen, produce female Bees. 

Dzierzon therefore asserts that every egg laid without fer- 
tilization by a queen-bee produces a drone, and that every 
fertilized egg laid by her produces a worker or a queen, according 
as the larva excluded therefrom is nourished with worker-food or 
royal- food. 

This proposition of Dzierzon's theory necessarily made the 
greatest noise when it was first expressed, and requires above all 
to be submitted to the closest examination. Before I undertake 
this examination, I will only remark that one circumstance 
speaks a priori in favour of this proposition of Dzierzon, 
namely, that by adopting this proposition, every phenomenon, 
however remarkable, in the sexual existence of the Bees may be 
easily explained. But as a time-honoured physiological law is 
at once abolished by this proposition, namely, that an egg which 
is to be developed into a male or female individual must always be 

* See Bienenzeitung, 1855, p. 201. 



54 PARTHENOGENESIS 

fertilized by the male semen, the affair appears of sufficient im- 
portance to be weighed and examined from all sides with the 
utmost care. I have taken the trouble upon myself and tested 
Dzierzon's assertion with all the means at my command, by 
which I have convinced myself in the following way of its 
correctness. 

In the first place, I may appeal to the fact, that it is a general 
occurrence amongst Insects, that the females, even when they 
have not copulated, deposit their mature eggs without fecunda- 
tion ; it is therefore nothing remarkable that a virgin queen 
deposits eggs. But we must be astonished that these eggs, 
although unfecundated, do not remain undeveloped ; nay, what 
is more, that only drones, or male Bees, are produced from such 
eggs. As to the truth of this phenomenon, plenty of observa- 
tions are adduced by the Apiarians, of which I bring forward, 
only as the most convincing example, the drone-productiveness 
of a virgin queen with imperfect wings. Every observant and ex- 
perienced Bee-keeper knows the ill consequences introduced by 
a queen-bee which has been excluded with crippled wings, and 
which has acquired the dominion of a bee-hive. She finds her- 
self prevented from undertaking the wedding-flight, but follows 
the impulse to oviposition, and supplies worker- cells and drone- 
cells indiscriminately with unfecundated eggs; these arrive at 
development, the larvae excluded from them are provided with 
nourishment by the workers, they grow up, but all of the same 
size and the same nature ; for they are all drone-larvae, of which 
those which have grown in worker-cells cannot find room in 
these, and therefore the workers elevate their narrow cells by 
subsequent additions, so as to obtain room, and in this way pro- 
duce misshapen combs, or combs with the so-called crooked brood 
[Buckelbruf) . 

A very interesting experiment was made by Berlepsch in 
order to confirm the drone-productiveness of a virgin queen. 
He contrived the exclusion of queens at the end of September 
1854, and therefore at a time when there were no longer any 
males ; he was lucky enough to keep one of them through the 
winter, and this produced drone-offspring on the 2nd of March 
in the following year, furnishing 1500 cells with crooked brood*. 

* See Bieneazeitung, 1855, No. 7- p. 76. 



IN THE HONEY-BEE. 55 

That this drone-bearing queen had really remained a virgin was 
proved by the dissection, which Leuckart undertook at the re- 
quest of Berlepsch*. 

The true cause of such a drone-productiveness in a bee-hive, 
however, could only be detected by an apiarian as acute and 
endowed with such a distinguished power of observation as 
Dzierzon, whilst up to this time the unfortunate occurrence of 
an excess of drone-brood in a bee-hive has been quite differ- 
ently and falsely understood by other Bee-keepers. They laid 
no stress upon the fact that such a hive only contained drone- 
brood, but they merely wondered that a hive governed by a queen 
with crippled wings contained any brood at all ; and they en- 
deavoured to explain this phsenomenon by the supposition that 
this unexpected brood could only be produced by a fertilized 
queen. But as the queen from which this brood was derived 
had been found to be crippled in the wings, they erred in respect 
to the affair of copulation, and supposed that this crippled brood- 
bearing queen was certainly fertilized, and that consequently the 
act of copulation was effected by the queen-bee within the hive. 
This erroneous conclusion of course brought in a number of 
other errors with regard to the signification of the particular 
Bee-individuals and their functions, by which a correct insight 
into the process of reproduction in the Bees must always have 
been disturbed. 

Dzierzon alone did not allow himself to be diverted from the 
right path in his observations; he maintained that the female 
Bee can only return fertilized to her hive after the performance 
of her wedding-flight. He did not, however, content himself 
with this matter of experience ; he went further in his rational 
way of investigating Bee-life ; he examined more closely the 
egg-laying and drone-bearing queens, which according to his 

* Leuckart found the state and contents of the seminal pouch of this queen 
to be exactly of the same nature (see Bienenzeitung, 1855, p. 128) as I had 
found in other virgin queens (see Germar's Zeitschrift fur die Entomol. 18-13, 
p. 374). The seminal receptacle in all these females never coutained semen- 
masses with their characteristic spermatozoids, but only a limpid fluid, desti- 
tute of cells and granules, which is produced from the two appendicular glands 
of the seminal capsule, and, as I suppose, serves the purpose of keeping the 
semen transferred into the seminal capsule in a fresh state, and the spermato- 
zoids active, and consequently capable of impregnation. 



56 PARTHENOGENESIS 

observations were to be regarded as virgins; he tore away 
the apex of their abdomen, by which means he succeeded in 
getting a sight of the seminal receptacle, which in a female Bee 
is of the size of a pin's head. Dzierzon knew from experience, 
that a fertilized Bee in the normal state contains a milk-white 
seminal capsule, which when crushed gives issue to the milky 
seminal fluid. He knew that the empty seminal capsule of a 
newly excluded virgin queen is not milk-white, but limpid; and 
he convinced himself that in those drone-bearing queens with 
crippled wings the seminal receptacle was limpid and empty of 
semen, and consequently in the same state as the seminal cap- 
sule of a virgin queen. I have spoken with Dzierzon upon these 
observations ; and as, from my own microscopical examination, 
I was well acquainted with the state of the sexual organs of 
virgin and fertilized queens, I was thus in a position to judge 
quite safily, from the description which Dzierzon gave me of 
his investigations, made without a microscope, that he had ac- 
quired perfectly correct notions as to the difference in the con- 
dition of the sexual organs of a virgin and fecundated female 
Bee, and therefore could not well have deceived himself in this 
respect*. 

Moreover, I felt myself the less inclined to doubt the correct- 
ness of these observations of Dzierzon's just reported, as I could 
not but remember that, according to my own observations, the 
females of certain Psychida lay unfertilized eggs which are also 
developed, but, inversely, instead of males produce nothing but 
females. Dzierzon, however, by other observations furnished 
me with evidence in favour of his proposition, that drones alone 
are always produced from unfertilized Bees' eggs when they are 
developed, and that consequently, in order to obtain drone-brood, 
it is not necessary that the queen-bee should fertilize the eggs 
when laying them. As I have already mentioned (p. 39), it 
happens now and then in a bee-hive, especially when it has lost 

* Berlepsch has also seen drone-production and crooked combs caused in 
the same way in bee-hives which were inhabited by a queen with crippled 
wings, which had consequently remained without copulation. See (in the 
Bienenzeitung, 1855, No. 7. p. 75) the important and interesting letter addressed 
to me by Berlepsch, in which he discusses the question, whether the drone- 
eggs are fecundated. 



TN THE HONEY-BEE. Of 

its queen, that individual workers lay eggs. This phenomenon 
has long been known to every experienced Bee-keeper ; nay, it 
had already been observed, that only drones are developed from 
these eggs laid by workers*; but it is only from the attentive 
observer Dzierzon that we know why such egg-laying workers 
are always the parents of drones, or, in other words, why only 
drones are always developed from these eggs produced by 
workers, if they attain to development. This phenomenon stands 
in the closest connexion with the drone-productiveness of the 
virgin queen-bees already mentioned. 

It was ascertained anatomically by Mademoiselle Jurine, that 
the worker-bees are nothing but female Bees whose sexual or- 
gans are aborted f. By careful dissection the ovarian tubes not 
perfectly developed may be exhibited in all workers, connected 
with an undeveloped oviduct. I have already shown in the year 
1843, that in all workers, there is connected with this undeve- 
loped oviduct, an appendage which perfectly represents the 
seminal receptacle of the queens. On this appendage I could 
discover the seminal duct, the seminal capsule, and the two 
appendicular glands, with their common efferent duct in the 
workers, but all these separate parts of the seminal receptacle 
were in a very undeveloped state J. 

In what follows, I will endeavour to explain by what cause 
the ovarian tubes, which in the normally-formed workers always 
remain empty, may become exceptionally filled with eggs in 
certain workers. It is well known to Apiarians, that in hives 
which have suddenly lost their queen, the workers, if they wish 
to put themselves in possession of a new queen, select some 
worker-cells furnished with an egg or a young larva, and enlarge 
these into royal cells (queen's cradles), and that they do not 
then bring up the larvae which are excluded from the eggs al- 

* See Huber, Nouvelles Observations sur les Abeilles, p. 194. Even in the 
time of Aristotle similar observations had been made, as appears from these 
words: — "Dicunt indicio esse, quod fucorum foetus innascantnr etiam, ubi 
reges absint, apum autem non innascantur." See Aristotelis de Animalibus 
Historic, lib. v. cap. 18 (ed. Schneider). 

t See the works of Huber and Ratzeburg already quoted (p. 3). 

X See my memoir upon the Receptaculum seminis of the female Hymen- 
optera. Germar's Zeitschrift fur die Entomol. bd. iv. p. 375. 



58 PARTHENOGENESIS 

ready laid in these former worker-cells, or which were found by 
them already excluded in such cells, with the ordinary worker- 
food, but furnish them with royal-food, as indeed all the eggs 
deposited by a fertilized queen in worker-cells are of one kind, 
namely female. But in order that the female sexual organs of 
such a larva may acquire their development, the larva must 
receive royal-food ; if, on the contrary, the female sexual organs 
are to remain undeveloped for the advantage of the organs of 
the worker-bee, destined for work, this object is attained by the 
administration of worker-food. I leave it undecided in what 
the distinction between the worker- and royal-food consists ; 
for the Apiarians have hitherto been at variance, as to whether 
the larvae of workers and queens received the same food, but the 
latter in greater quantity, or whether the queen's food differed 
from that of the workers not only in its quantity, but also in its 
quality. From Leuckart's recent investigations*, however, it 
appears that there really is a qualitative difference between 
the two kinds of food. The larvae destined to become workers 
only receive the paste prepared by the workers in their digestive 
organs during the first days of their life, whilst in the latter days 
of their larval existence they are fed with pollen and honey; the 
queen-larvae, on the contrary, are supplied with the above paste 
during their whole larval existence. Leuckartf found the first 
traces of the internal genital organs in the female larvae of six 
days old ; it is exactly at this time that the change of food takes 
place in the worker-larvae, which up to this period are nourished 
just like the queen-larvae with the same paste. In this way we 
get an explanation of the circumstance which has been observed 
by most experienced Apiarians, that a female larva does not re- 
quire the usage of a queen from its earliest period in order to 
become perfectly sexual, but that worker-larvae, even several 
(six or seven) days old, may also be reared to queens, when 
their narrow cells are subsequently enlarged, and they are abun- 
dantly supplied with royal-paste, instead of with workers'-bread 
(pollen and honey). 

If then it is certain that a worker-bee or a queen may be 
reared indifferently from every larva of a worker-cell derived 

* See his Secbacher Studien in the Bienenzeitung , 1855, p. 209. 
t See Leuckart, loc. cit. supra, p. 210. 



IN THE HONEY-BEE. 59 

from a fecundated queen, the case may probably occur in one 
bee-hive or another, that, by some confusion or disturbance in 
the regular distribution of the food, some of the royal-food falls 
to the lot of one or several worker-larvae in the neighbourhood of 
a queen's-cell, into which royal-food is carried, by which their 
sexual organs are more or less developed. By this influence the 
development of the female genitalia may have been abnormally 
elevated in a worker, up to the power of laying true eggs*. Such 
egg-laying workers, however, always remain unfecundated ; they 
do not feel like perfect female Bees, and undertake no wedding- 
flight ; which, indeed, would be of no use to them, as the deve- 
lopment of their copulative and fecundative organs has not kept 
pace with that of their ovaries and oviducts. The external 
sexual organs, as well as the seminal receptacle, remain abortive 
in these egg-laying workers, for which reason they are not in a 
condition to copulate and receive fertilizing semen. They will 
therefore only be able to lay unfecundated eggs, from which, if 
they actually arrive at development, only male Bees are pro- 
duced, no matter whether they were laid in worker-cells or drone- 
cells. The cause of the production of an excess of drones and 
crooked combs in a queenless hive is therefore, that as regards 
the nature of her deposited eggs, an egg-laying worker-bee is in 
exactly the same position as an egg-laying virgin queen, — both 
can only be the parents of drones. 

Why the egg- laying workers can only lay unfertilized eggs, I 
have already explained in my letter to Baron von Berlepschf. 
At that time, indeed, I had not been enabled to dissect an egg- 
laying worker-bee ; so that the principal proof of the correctness 

* Huber (Nouvelles Obs. sur les Abeilles, p. 202) was already acquainted 
with these occurrences in the bee-hive, and endeavoured to explain them in 
the same way. 

[Hunter's observations had not extended his knowledge beyond the fol- 
lowing point : — " As soon as a few combs are formed, the female Bee begins 
laying of eggs. As far as I have been able to observe, the queen is the only 
Bee that propagates, although it is asserted that the labourers do. Her first 
eggs in the season are those which produce labourers, then the males, and 
probably the queen. This is the progress in the Wasp, Hornet, Bumble- 
bee, &c. However, it is asserted by Riem, that when a hive is deprived of a 
queen, labourers lay eggs." — "On Bees," Phil. Trans., 1/^2, p. 152.— R. O.] 

t See Rienenzeitung, 1854, p. 231. 



60 PARTHENOGENESIS 

of my views as to the drone-productiveness of the workers still 
had to be obtained. This proof, Baron von Berlepsch has since 
furnished by dissecting a worker-bee which was laying drone- 
eggs, and rinding therein a small ovary with about eight pretty well 
developed eggs, but no seminal receptacle*. He did not content 
himself with this investigation of his ownf, but in order to make 
the unbelieving Apiarians more inclined to accept the truth, he 
also called in the assistance of an entomotomist. At the request of 
Berlepsch, Leuckart of Giessen dissected at Seebach two workers 
taken in the act of laying eggs, of which, unfortunately, one 
individual, as Leuckart reported J, was no longer in good con- 
dition ; but on the other hand, in the second individual he was 
able to prepare the sexual apparatus with its different parts in 
connexion, and to recognize the egg-laying Bee from its con- 
struction at the first glance. On the right side he found six, 
and on the left five, ovarian tubes, with single mature eggs. 
The single oviduct, as Leuckart said, was without appendages. In 
the first-mentioned egg-laying worker also, Leuckart could detect 
no seminal receptacle, although this structure is still distinctly 
recognizable in the queens, even when the other entrails are 
almost entirely dissolved by decomposition. I must here recall 
the fact that, as I have already mentioned (p. 57), the seminal 
receptacle is not entirely wanting in the workers, but that it 
remains undeveloped in them, and may be detected as a small 
appendage to the oviduct by a close microscopical examination. 
Leuckart overlooked this appendage in the egg-laying Bees 
examined by him, but has convinced himself, as he himself 
admits §, by subsequent investigations, of the presence of the 
rudimentary seminal receptacle in worker-bees. At any rate, 
it appears from the investigations of Berlepsch and Leuckart, 
that, in the egg-laying workers dissected by them, the seminal 
receptacle was not present in the same degree of development as 

* See Bienenzeitung, 1855, p. 78. Huber also (see his Nouvelles Observ. 
p. 192) dissected some of these egg-laying workers, and found in one indivi- 
dual eleven, and in the other four, mature eggs. 

t That Herr von Berlepsch has acquired the art of dissecting a Bee, I 
had the opportunity of convincing myself last summer with my own eyes, 
during my visit to Seebach, which will be mentioned further on. 

% See Bienenzeitung, 1855, p. 203. 

§ Bienenzeitung, loc. cit. p. 211. 



IN THE HONEY-BEE. f> 1 

in the queen-bee, as in its perfectly developed state it is visible 
even to the naked eye, of the size of a pin's head, and conse- 
quently could not have escaped the notice of those two observers. 
Another cause of drone-productiveness in a bee-hive may 
also be explained consistently by Dzierzon's theory. Thus 
in certain, but undoubtedly very rare cases, it happens that 
fertilized queens in advanced age towards the end of their 
vital activity become drone-bearing, after showing themselves 
to be normal up to that period as regards the production of 
drones, females, and workers ; normal fertilized queens, there- 
fore, in course of time lose the faculty of producing workers and 
females ; the brood deposited by such old queens can only be 
reared to male bees, — certainly, according to Dzierzon's theory, 
for the self-evident reason, that the store of semen in the seminal 
receptacle of a fertilized queen is gradually exhausted. As a 
queen only undertakes the wedding-flight once in her life, and 
fertilizes many thousands of eggs destined for the worker-cells 
for several consecutive years, with semen received by a single 
act of copulation*, although only one or two spermatozoids of 
the male semen are employed in the fecundation of one egg, yet 
the seminal mass will at last be used up, and at the same time 
the old queen will lose the faculty of laying the required number 
of fertilized eggsf. 

* According to a statement made to me by Dzierzon, a qneen may acquire 
the power of laying fertilized eggs for five years, by a single normally executed 
copulation. 

f Upon this subject I may allow the experienced Apiarian Von Berlepseh 
to speak, as he has done in the Bienenzeitung (1855, p. 78) in the following 
words : — " It is a fact, that queens, when their fertility is on the decline, lav 
a greater or less number of drone-eggs in worker-cells amongst female eggs ; 
nay, even with extremely fruitful queens, it by no means rarely happens, 
that individual drones escape from worker-cells in the midst of workers. 
How is this explicable except by Dzierzon's hypothesis, as even in this 
case the queens evidently wish to lay, not male, but female eggs ? Lean- 
ing upon Dzierzon's hypothesis, I conjecture that in queens whose fertility is 
already on the wane, every egg can no longer be fertilized, because the recep- 
tacle is no longer sufficiently filled with semen, but that in queens which are 
still in the full power of their fertility, an egg which ought to be fertilized may 
now and then glide past without fecundation ; a spermatozoon may not ad- 
here, or may be lost again before it can penetrate through the micropyle into 
the yelk." 



62 PARTHENOGENESIS 

From the circumstances hitherto described it will be evident, 
how a queen which has not been fertilized, or an old queen or 
egg-laying worker, must act injuriously upon a colony of Bees ; 
they constantly cause confusion in a bee-hive, as they only 
produce lazy drones, and cannot, by the production of new 
workers, replace the loss of workers, to which every bee-hive is 
exposed. On the other hand, a colony of Bees which rejoices in 
the possession of a vigorous, fertilized queen will thrive well, as the 
drones, the workers, and the queens required for the emigration 
of young swarms, are produced by her at the right time, and in 
the proper proportions as to number, for which purpose the 
workers prepare and arrange the necessary drone-cells, worker- 
cells, and queen-cells. 

Dzierzon's theory also includes the assertion that every nor- 
mally organized and fertilized queen must at the same time 
possess the power of laying male or female eggs at will, that is 
to say, of leaving an egg unfertilized, or depositing it fecundated 
at will, when engaged in laying her eggs. 

The answer to the question, how a queen can know when she 
has to lay a male or female egg, will be, that instinct will tell 
her, and truly, at the moment when she pushes her abdomen 
into a wide drone-cell, or the narrow cell of a worker, for the 
purpose of laying an egg. The distinction of the wider and 
narrower cells will certainly be felt out by a normal queen with 
her abdomen, and by this sensation she will know, that she 
must fertilize the egg to be deposited in a narrow cell, whilst 
she has to lay down the egg without fecundation in a wide one. 
By the peculiar texture of an incomplete royal-cell too, a normal 
queen will be instinctively induced to fertilize the egg to be 
deposited in it. By this means Dzierzon might have explained 
that phenomenon in the bee-hive which has always excited 
astonishment as a wonderful mystery, namely, that faculty 
possessed by the normal queen of furnishing the drone-cells, 
worker- cells, and queen-cells of the combs, which are arranged in 
different number and order in every bee-hive, with the right eggs. 
It would certainly still remain to be proved, from the organi- 
zation and arrangement of the separate sections of the female 
sexual organs, that it really was possible for a fertilized queen, 
by the presence of decidedly voluntary muscles, to retain the 



IN THE HONEY-HEE. (J.$ 

semen in the seminal receptacle or evacuate it at will. From 
the investigations above referred to (p. 4) which I made upon 
fertilized female insects, it appears that by the copulation of 
Insects the ovaries are not fecundated, but that the seminal re- 
ceptacle is filled with semen, and that the fecundation of the 
egg only takes place during oviposition at the moment when the 
egg to be laid slips by the orifice of the seminal receptacle in 
the oviduct. With regard to this I may refer to those female 
insects, which, after the completion of copulation, survive their 
males in the autumn, hybernate with the ovaries imperfectly 
developed, and only lay fertilized eggs capable of development 
in the following spring, after their ovaries have become filled 
with mature eggs*. Such females, therefore, preserve the male 
semen received during copulation in their seminal receptacle, 
keep it fresh, probably by the aid of the secretion of the appen- 
dicular glands of the seminal capsule, and evacuate it at pleasure 
when required during the act of laying. For this purpose par- 
ticular voluntary muscles do really exist ; I have observed them 
in the vicinity of the exterior of the seminal capsule in many 
female Beetles f. In the immediate vicinity of the seminal re- 
ceptacle of female Bees also, I have seen voluntary muscles, 
without, however, being able to state with certainty what definite 
functions they have to perform. From this, the possibility of a 
voluntary evacuation of semen from the seminal receptacle of 
fecundated female insects could certainly not be denied, espe- 
cially as the voluntary deposition of male and female eggs by a 
queen-bee may be proved by the brood produced from her. 
After I had called the attention of Von Berlepsch to the exist- 
ence of voluntary muscles at the seminal receptacle, he expressed 
himself upon this point in the following way J :— " Probably the 
queen has the faculty of closing the orifice of the receptacle at 
pleasure, perhaps by the contraction of the whole vesicular mem- 
brane, or even that of removing and somewhat retracting the 

* See upon this point my observations on hybernated fertilized female 
Wasps and Gnats, in Wiegmann's Archiv fur Naturgeschichte, 183?), bd. i. 
p. 107, and in Germar's Zeitschrift fur die Entomologie, bd. ii. 1840, p. 443. 

t See my investigations Ueber die Spermatozoen in den befruchtetenlnsekfcn- 
Weibchen, in Miiller's Archiv, 1837, p. 398. tab. 20. figs. 1 & 2 </. & p. 42A. 

X Bienenzeituny , 1855, No. 7- p- 77- 



64 PARTHENOGENESIS 

whole receptacle sideways from the tube of the oviduct into 
which it opens, so that those eggs which she wishes to deposit 
in male cells may glide past untouched by the semen/' 

The power of a fertilized queen to lay male or female eggs 
at pleasure, may also be proved by the following experiment. In 
a Dzierzon hive we may, to a certain extent, compel a fertilized 
queen to lay male or female eggs. The construction of one of 
these hives permits the nature of the combs prepared in it by 
the workers to be closely inspected : if the workers of a hive 
furnished with a normal queen prepare too many drone-cells, 
which we may perhaps not wish to have, or if the hive requires 
more workers, we may remove the drone-combs, whose cells the 
queen would have shortly supplied with male, that is to say, 
unfertilized eggs, and instead of these suspend combs with empty 
worker-cells ; the queen will furnish these combs also with eggs, 
and indeed, to correspond with the nature of the cells, with 
female or fertilized eggs, from which the workers may rear their 
like. In the summer we may induce the queens of populous 
hives to lay drone-eggs, if we suspend an empty drone-comb in 
the midst of the hive. From this it follows that the intelligent 
Bee-keeper has it in his own hands in what direction he will 
turn the activity of this or that colony of Bees, and that by 
suitable assistance he may prevent the disorganization and de- 
moralization of a bee-hive. 

Before I turn to the strictly scientific proofs which I have 
still to furnish, in order to give permanence to the view upon 
the reproduction of the Bees put forward by Dzierzon only as 
a hypothesis, and raise it to the rank of a theory, so that it 
may take its proper place in the history of animal development, 
I wdll here cite a few more empirical proofs, by which alone the 
correctness of Dzierzon's theory would be convincingly shown, 
if its importance did not require still more impressive facts for 
its establishment. 

I must not omit to mention that Dzierzon himself, after calling 
a number of opponents into the field by the promulgation of 
his new theory, and after all possible imaginable objections had 
been raised from the most various sides against its correct- 
ness, began to doubt the perfect tenability of his theory. Not- 
withstanding that very recently Dzierzon expresses himself 



IN THE HONEY-BEE. 65 

with peculiar reserve and caution upon certain points of his 
theory*, other experienced Apiarians still held firmly to it, as 
after it had once become perfectly familiar to them, by its 
assistance every occurrence in a bee-hive, however unexpected 
or apparently strange, was instantly understood by them. 

Above all we must here mention Herr von Berlepsch, who 
has set himself the task of testing Dzierzon's theory in every 
direction, with his abundance of bee-hives. His establishment 
of Bees, which is most carefully attended to, and kept in the 
most exemplary order, also offers quite uniquely in its kind, by 
the disposition, arrangement and mass of its materials, the best 
and most certain opportunity of testing and answering those 
questions relating to Bee-life raised by Dzierzon. 

The following extremely interesting experiments were made 
by Berlepsch, which must again convert Dzierzon himself, since 
he appears to have become a doubter of his own theory. 

In May 1854 Berlepsch caught an old fertile queen f, and 
confined her in a small queen's cage, in order to incorporate her 
with a new colony of Bees after its establishment. She was in 
the normal state, and up to that time had produced the neces- 
sary drones and workers. Berlepsch gives the following account 
of this queen : — "As I was closing the lid (of the queen's cage), 
which ran in a groove, I pinched the queen so strongly at the 
apex of the abdomen, that she contracted the whole abdomen 
like a bee that has been stung, and allowed it to drag after her. 
I thought at first that she was lost, but as she was still living 
an hour afterwards, and sitting again extended and quiet, I gave 
her back to her people. She laid, as before, thousands of eggs, 
but from all these nothing but drones were henceforward deve- 
loped. If I had only dissected this queen as soon as I became 
aware of her drone-productiveness, I should at least have seen 
whether the (seminal) vesicle was still in existence and normally 
filled. But I delayed the dissection, and when at length I 
wished to undertake it, the queen was gone. This certainly 
very remarkable occurrence, which speaks loudly in favour of 
Dzierzon's hypothesis of the unfecundated state of all male eggs, 

* See his Bienenfreund aus Schlesien, 1854, No. 8. p. 64. 
t See the letter addressed to me by Berlepsch in the Bienenzeitung, 1855, 
No. 7- p. 7$. 

F 



66 PARTHENOGENESIS 

was communicated by me privately to President Busch for his 
opinion, as I could not then form any definite opinion for my- 
self, not knowing with certainty that the vesicle is the recepta- 
culum seminis, and the white slime (its contents) the sperma 
virile. Busch, however, was also unable to form an opinion ; 
my servant Gunther on the contrary thought, that perhaps the 
receptaculum had been crushed and destroyed. This, however, 
I regard as extremely improbable, as the crushing of the recep- 
tacle, which is generally very firm, between the soft surrounding 
parts of the body of the queen, without quickly leading to the 
death of the latter herself, is scarcely possible ; I believe, there- 
fore, that it was only that the organs which may act in opening 
and closing the orifice, or in retracting and advancing the re- 
ceptacle, were lamed, stiffened," &c. 

If I am to express my opinion upon this interesting case, 
I suppose that by the pinching of the abdomen the seminal re- 
ceptacle of the queen, filled with semen, was torn away from the 
oviduct at its opening point, by which the queen, thus injured, 
was no longer enabled to fertilize her eggs during deposition, 
and therefore could only lay unfertilized and consequently male 
eggs. 

Berlepsch reports as follows* upon another experiment con- 
firmatory of Dzierzon's principal point, which he made in con- 
sequence of studying J. Muller's Physiologie des Menschen : 
"Now only did I obtain a full conviction of the existence of 
the spermatozoa ; and when I read in the above-mentioned work 
(bd. ii. p. 636) that high and loiv temperatures cause the move- 
ments of the spermatozoa to cease, I thought to myself: Now you 
have the complete explanation of Dzierzon's casef; and if it be 
true that in Apis mellifica the male eggs regularly develope 
themselves spontaneously into males, but are only converted 
into female eggs by the fecundation of the spermatozoa, every 
normally fruitful queen must cease to lay female eggs, from the 
moment when we succeed in rendering the spermatozoa motion- 

* See his letter quoted above, p. 61. 

f Berlepsch here refers to the case communicated by Dzierzon (Bienen- 
zeitung, 1854, p. 252. 2), that a queen which had been frozen for a long time, 
after being again brought to life by warmth, only laid male eggs, whilst pre- 
viously she had also laid female eggs. 



IN THE HONEY-BEE. 67 

less (killing them) without destroying the mother herself. At 
the end of June 1854, therefore, I took three very fruitful queens, 
imprisoned each of them in a queen's cage, went to Miihlhausen 
and placed the cages in the ice-cellar of an inn-keeper who was 
a friend of mine. There I left them for about thirty-six hours. 
The queens were of course completely benumbed, regularly 
covered with hoar frost, and when I returned with them to 
Seebach, I exposed them to the sun, which was just rising. For 
a long time none of them stirred ; at last, towards seven o'clock, 
I observed movements of the feet in one of them. By means 
of a fine bit of w T ood I put a little honey upon her proboscis, and 
in ten or twelve minutes more, she had again returned to life. 
The two others on the contrary were dead. This appeared very 
remarkable to me, as even worker-bees, whose vitality, however, 
is very much weaker than that of the queens, generally survive 
such a short freezing ; and the only reason I can find for it, is, 
that the temperature of the ice-cellar was too low, and therefore 
the queens were too much penetrated by the frost, if the circum- 
stance that the queens were too heavy with eggs, and therefore 
less able than at other times to bear external injurious influences 
upon their bodies, may not have cooperated to produce death. 
I returned the revived queen to her people. She laid, as before, 
thousands of eggs, but from all of them only males were evolved. 
When I subsequently examined the semen, I found it less con- 
sistent and with a yellowish tinge." 

From this extremely interesting experiment, it follows evi- 
dently that the male eggs of the Bees require no fertilization ; 
the spermatozoids which this queen, exposed to such an intense 
cold, contained in her seminal receptacle, were certainly be- 
numbed, and did not again become capable of movement after 
the thawing ; so that therefore this queen could only have laid 
unfecundated eggs ; for even if she had emptied the contents of 
her seminal receptacle over the eggs when laying them, in order 
to fertilize them, the numbed spermatozoids would have remained 
incapable of action. 

A third empirical proof, by which the principal point of 
Dzierzon's theory of reproduction is supported, is furnished by 
the phenomena which maybe observed in the production of mules 
amongst Bees. Attention has only been directed to the pro- 

F 2 



G8 PARTHENOGENESIS 

duction of hybrid Bees at a very recent period, since the Italian 
race of Bees has been introduced into Germany by Dzierzon 
and Berlepsch. The so-called Italian Bees form no separate 
species, but must only be regarded as a variety of the Apis 
mellifica. These Italian Bees are distinguished at the first 
glance by the leather-yellow colour of their abdomen from the 
unicoiorous blackish-brown German Bees. In the females and 
workers of the Italian race, the first, second and third abdominal 
segments appear of a rusty-yellow colour {colore rufo-ferrugineo) 
and margined with black ; this black margin is very narrow on 
the first segment, broader on the second, and broadest on the 
third. The Italian drones have the middle of the hinder margin 
of the second, third and fourth, and often that of the fifth 
abdominal segment broadly rusty-yellow, by which the blackish- 
brown abdomen of these drones appears to be furnished on the 
back with from three to four rusty-brown transverse bands, of 
which the first is the broadest. The German drones, on the 
contrary, have the abdominal segments only narrowly margined 
with rusty -yellow*. According to the statements of Dzierzon 

* This variety of Apis mellifica has already been for an extraordinary 
length of time indigenous in Italy and the South of Europe generally, for 
Virgil, and before him Aristotle, mention these rusty-yellow Bees in their 
descriptions of the ceconomy of Bees. But unicoiorous dark Bees must also 
have occurred constantly amongst the variegated or rusty-yellow spotted 
Bees, as both authors also speak of black Bees. In Aristotle's De Ani- 
malibus Historic, lib. v. cap. 18. 2, we find,—" Regum autem genera duo ; 
praestantior rufus : alter niger et varius magis." And further, lib. v. cap. 19. 1, 
" In genere apum praestantissima quae parva, rotunda, varia ; alteram genus 
est oblongum et vespae (Anthrenae) simile : tertium furem vocant : niger is, 
alvo lata. Quartus fuscus, omnium maximus, sine aculeo, ignavus." The 
verses of Virgil, in which {Georgicon, lib. iv. 91) he declares the variegated 
Bees to be more valuable than the black ones, are well known : — 

" Alter erit maculis auro squalentibus ardens : 
Nam duo sunt genera : hie melior, insignis et ore, 
Et rutilis clarus squamis ; ille horridus alter 
Desidia, latamque trahens inglorius alvum. 
Ut binae regum facies, ita corpora plebis. 
Namque aliae turpes horrent : ceu pulvere ab alto 
Quum venit, et sicco terram spuit ore viator, 
Aridus ; elucent aliae, et fulgore coruscant, 
Ardentes auro et paribus lita corpora guttis. 
Haec potior suboles." 



IN THE HONEY-BEE. 69 

and Berlepsch, who have done especial service to the breeding 
and diffusion of the Italian Bees in Germany*, these golden- 
yellow Bees are not only more beautiful, but also more indus- 

The statements also which Varro and Columella have made upon Bee-keeping, 
show that in Italy the gold-coloured or variegated Bees and the unicolorous 
blackish-brown Bees occur together. See Scriptorum rei rusticce veterum la- 
tinorum (ed. Schneider), torn. i. p. 316. Varronis lib. hi. cap. 16:— "Ut qui- 
dam dicunt, tria genera cum sint ducum in apibus, niger, ruber, varius, ut 
Menecrates scribit duo, niger et varius : qui ita, melior ; ut expediat mellario, 
cum duo sint eadem alvo, interficere nigrum, quem scit cum altero rege esse 
seditiosum, et corrumpere alvuui, quod fuget, aut cum multitudine fugetur. 
De reliquis apibus optima est parva, varia, rotunda." Columella (lib. ix. 
cap. iii. op. cit. supra, torn. ii. P. i. p. 43/) in the description of the Bees 
refers to the statements of Aristotle and Virgil, and says of the queens 
(cap. x. op. cit. p. 453), — " Sunt autem hi reges majores paulo et oblongi 
magis quam caeterse apes, rectioribus cruribus, sed minus amplis pinnis, 
pulchri coloris et nitidi, levesque ac sine pilo, sine spiculo, nisi quis forte 
pleniorem quasi capillum, quem in ventre gerunt, aculeum putet, quo et ipso 
tameu ad nocendum non utuntur. Quidam etiam infusci atque hirsuti reperi- 
untur, quorum pro habitu damnabis ingenium." Therefore, even amongst the 
Romans, the variegated and golden-yellow Bees were more highlv valued than 
the unicolorous blackish-brown race. That this rusty-yellow variety of the 
Honey-Bee is at present very widely diffused in Italy, appears from the descrip- 
tion which Spinola (Insectorum Ligurice species novce aut rariores, torn. i. 
1806, p. 35) has given of a Piedmontese Honey-bee. This Bee, furnished by 
Spinola with the name of Apis ligustica, agrees exactly, according to the 
description, with the rusty-yellow Bees recently introduced amongst us from 
Italy. Two individuals of the Apis ligustica, captured near Bellinzona and 
Sesto Calende on the Lago Maggiore, which I have been able to compare 
here with some Italian Bees of the true race bred in Seebach, I cannot re- 
cognize as a separate species, but only as a rusty-yellow variety of the Apis 
mellifica, the unicolorous dark form of which, according to Spinola's own 
statements (op. cit. p. 133), also occurs, although rarely, in Piedmont. The 
aurora-coloured Bees mentioned by Delia Rocca (Traite complet sur les 
Abeilles, 1/90, torn. ii. p. 142), and said to have been introduced into France 
from Holland or Flanders, may have belonged to the same Italian variety. 
The Egyptian Honey-bee also, described by Latreille (Annates du Museum, 
torn. v. 1804, p. 171) under the name of Apis fasciata, is probably nothing 
but this southern rusty-yellow variety of the Apis mellifica, especially as 
Latreille himself admits that this Egyptian hive-bee agreed exactly with a 
kind of Honey-bee taken near Genoa. 

* Herr von Baldenstein of Graubiindten has the merit of having first 
directed attention to the Italian Bees as an object adapted for experiment 
I see the Bienenzeilung, 1848, p. 26). He had got an Italian bee-hive con- 



70 PARTHENOGENESIS 

trious and better-tempered than the German Bees. These 
latter properties are also the cause of the Italian Bees having 
become so much liked amongst us, and of so great a demand 
having recently arisen for them, so that Berlepsch found him- 
self under the necessity of declaring publicly*, that "If the 
Italian good-tempered, industrious race, ivith its beautiful colour 
is to be kept pure and stereotyped, perhaps even improved 
Dzierzon and I must be left in peace for at least one summer" 

It is a well-known fact, that by the crossing of different races 
of a species of animal, hybrid forms are produced, which unite 
in various ways certain characters of the two individuals of 
different races which were employed for the production of such 
race-hybrids. It was natural to suppose that in the Bees, the 
production of such race-hybrids must be combined with very 

veyed over the mountains, in order to make use of the difference of colour 
which occurs between the rusty-yellow Italian Bees and the unicolorous dark 
Swiss and German Bees in his observations. In the following year he per- 
ceived that his Italian Bees degenerated in the mother-hive, a part of the new 
brood being quite Italian; whilst another part, on the contrary, appeared more 
or less like the Swiss Bees. From this phenomenon Baldenstein correctly 
concluded that the young Italian mother-bees must have copulated with a 
Swiss male bee, and certainly outside the hive : this production of hybrids 
would not have taken place if the young Italian queens had copulated in the 
mother-hive, where they met with a sufficiency of true Italian drones. Balden- 
stein further mentions {Bienenzeitung , 1851, p. 81) that those Italian mother- 
bees, when he received them, were already four years old, and lived with him 
for three years more, therefore in all seven years ; they always produced true 
Italian Bees, by which it is proved that these queens required no fresh copula- 
tion after the first one. 

Incited by these interesting observations of Baldenstein's (see also the 
Bienenzeitung, 1853, p. 11), Dzierzon in February 1853 procured a bee-hive 
of the true Italian race (see Bienenzeitung, 1852, p. 204 ; and 1853, p. 40) 
from Madame Adele von Prollius, a zealous Apiarian at Mira near Venice, 
from which stock at Carlsmarkt (in Silesia) the other German Bee-keepers 
might be provided with Italian Bees, by the observations of which such im- 
portant scientific results have been obtained. For the various reports of the 
breeding of Italian Bees, see the Bienenzeitung for the years 1854 and 1855, 
and also the essay in that Journal for 1856, p. 1, in which Dzierzon discusses 
the question, — Is the Italian kind of Bee found by experience to be of the 
same importance for practice as for theory ? And, above all, read the im- 
portant communications of Berlepsch upon the Italian Bees (Bienenzeitung, 
1856, p. 3). * Bienenzeitung, 1856, p. 6. 



IN THE HONEY-BEE. 71 

peculiar modifications. If Dzierzon's theory proved correct, we 
might beforehand expect that by the copulation of a unicolorous 
blackish-brown German and a reddish- brown Italian Bee, the 
mixture of the two races would only be expressed in the hybrid 
females and workers ; but not in the drones, which, as pro- 
ceeding from unfecundatcd eggs, must remain purely German 
or purely Italian, according as the queen selected for the pro- 
duction of hybrids belonged to the German or Italian race. In 
fact, the expectations of the Apiarians were not disappointed. 
It is true that in these crossings of the races many remarkable 
occurrences, such as also happen, contrary to expectation, in the 
crossing of our larger domestic animals, were still necessarily left 
unexplained. According to Berlepsch's observations*, 1. many 
Italian mothers produce partly black and partly variegated 
Bees under all circumstances, that is to say, whether they have 
been fecundated by an Italian or a German drone ; 2. many 
Italian mothers produce only variegated Bees when they are 
fertilized by an Italian drone, but variegated and black ones 
mixed when the fertilization is effected by a German drone ; 
and 3. many Italian mothers produce only variegated Bees 
under all circumstances, that is to say, whether they are fer- 
tilized by an Italian or German drone. Such true Italian 
queens, adds Berlepsch, produce Italian Bees from the very 
first, when fertilized by Italian drones ; but, on the contrary, 
when fertilized by a German drone, they also produce German 
Bees at first, for a longer or shorter time. 

Here I must insist upon the fact, that these statements of Von 
Berlepsch only refer to the production of workers and female 
Bees, but by no means to drones. He endeavoured to explain 
these surprising and singular facts, which reposed upon two years 5 
experience, in the following manner. He refers to the existence 
of the appendicular gland so intimately connected with the semi- 
nal receptacle, to which I had even in the year 183Jf ascribed 

* See the Bienenzeitung, 1856, p. 5. 

t See my memoir Ueber die Sperrnatozoen in den befruchteten Insekten- 
Weibchen (Miiller's Archiv, 183/, p. 398). In this place I have said of the 
Glandula appendicularis,— " This organ probably serves for the secretion of a 
particular fluid, which is poured into the seminal receptacle and keeps the 
spermatozoa which remain here for a long time, alive." See also Germans 
Zeitschrift fur die Entomol. 1843, p. 368. 



h 



2 PARTHENOGENESIS 



the office of preserving by its secretion the seminal mass remain- 
ing for months in the seminal capsule, in a fresh state. Berlepsch, 
starting from this view, now thought, that the maternal liquor 
of the appendicular gland constantly penetrating (into the semi- 
nal receptacle) gradually permeates the spermatozoa to such an 
extent that their paternal elements are overpowered by the mater- 
nal ones. . If the mother-bee is of pure Italian blood, none but 
variegated Bees must be produced from her fertilized eggs, as 
soon as the spermatozoa derived from a German drone are suffi- 
ciently permeated ; but, on the contrary, if the mother be not 
purely Italian, black Bees will always remain. This conjecture, 
which I only quote here for the present as a conjecture, without 
saying anything for or against it, Berlepsch also endeavoured to 
support by the behaviour of a German queen, which, being fer- 
tilized by an Italian drone, produced last year variegated Bees 
amongst the black, but this year only black Bees. 

In all these observations with reference to the propagation 
and multiplication of the Italian race of Bees, the brood of drones 
always turned out purely Italian, or purely German, even when 
crossings occurred between the German and Italian Bees, accord- 
ing as the queen subjected to crossing belonged to the Italian or 
German race. But in order to attain certainty with regard to 
these phenomena, the observations to be made for this purpose 
must be performed with the greatest care. The observations 
will have to be made only with individuals of perfectly pure race, 
which will not always be obtained with ease and certainty, since 
the breeding of the Italian swarms side by side with the German 
bee-hives is already carried on amongst us to a very great extent. 
How difficult it may be to find a perfectly genuine and pure 
queen for such experiments, is shown by the mixtures of the two 
races of Bees in question, observed by Berlepsch and already 
referred to. I can therefore lay no very great stress upon an 
observation which Dzierzon made upon an Italian queen, and 
which, as I have already indicated (p. 64), has made this cautious 
Apiarian doubtful of his own theory. This isolated case, in 
which, moreover, some circumstance might probably have re- 
mained unnoticed, cannot overthrow a proposition, the correct- 
ness of which has been confirmed in so striking a manner by a 
number of other observations. How Dzierzon was surprised by 



IN THE HONEY-BEE. 73 

some such disturbing accident appears from his own statement, 
which I will give here literally, in order to show that Dzierzon 
is not one of those who cannot be led away from a preconceived 
opinion, whether it be right or wrong. His words* are as follow : — 

" Continued observations of the hybrid hives also must, be no 
less adapted to raise the veil more and more, to penetrate into 
the obscurity and finally bring the mysterious truth to light. If 
the drone-egg does not require fertilization, Italian mothers must 
always produce Italian drones, and German mothers German 
drones, even when they have been fertilized by drones of the 
other race. The Silesian Apiarian {Bienenfreund) possesses 
hybrid hives of both kinds, and did not permit any want of ob- 
servations so far as the limited time enabled him to make them, 
but he met with new unsolvable riddles. The Italian hybrid- 
mothers have throughout completely confirmed the supposition 
and produced the most beautiful Italian drones, one almost more 
beautiful than the genuine stocks, the maternal stock itself. Of 
two German hybrid hives, one also produced only the ordinary 
black drones ; the other the same, but unexpectedly amongst 
these a few appeared which glittered like gold, and were yellower 
than any single bee even in the genuine Italian hives. It cer- 
tainly was possible that even here a beautiful Italian amongst the 
workers, of which a portion had the colour of the indigenous Bees, 
and another portion that of the Italians, might have laid some 
eggs, from which the few yellow drones might have been pro- 
duced. Nevertheless the Silesian Apiarian is not particularly 
inclined to explain the phenomenon in this way, so as not to ex- 
pose himself to the suspicion that only a predilection for his hy- 
pothesis led him to have recourse to this explanation, as in point 
of fact the deposition of eggs by worker-bees when a queen is 
present, is an exceptional occurrence of the rarest kind. Although 
the vesicle filled with semen does not implant the vital germ for 
the drone in the egg, may not a peculiar emanation from it never- 
theless act in determining the kind and colour?" 

Dzierzon is certainly in the wrong, when, for the sake of this 
one observation which disturbs him, and in order to explain 
it, he again calls in the aid of the long-overthrown hypothesis of 
the action of an aura seminalis. Von Berlepsch has taken the 

* See the Bienenfreund cuts Schlesien, No. 8, 1854, p. 63. 



74 PARTHENOGENESIS 

trouble to invalidate this case detailed by Dzierzon, which is said 
to speak against his own theory. He very justly observes*, that 
in the preceding, Dzierzon has not established the fact that those 
few golden drones were actually produced by the queen, and not 
bv a very fine egg-laying Italian worker (as the half of the workers 
in this hive consisted of these); for although the presence of an 
egg-laying worker together with a queen is a case of the very 
rarest occurrence, yet it can be proved that such exceptions do 
occur. Berlepsch also points out with reason, that Dzierzon 
was never perfectly certain on the point whether the queen, in 
whose hive he observed the remarkable yellow drones, was by 
birth of true German race, or produced from hybrid brood. 
Dzierzon himself adds the warning to the statement of his casef* 
that in such observations great caution is necessary to avoid 
erroneous conclusions, as on such occasions we must be perfectly 
sure that the queen belongs by birth to the right race ; for if she 
has been produced from hybrid brood, it is impossible for her 
to produce even pure drones, but she produces half-Italian and 
half-German drones. However, I regarded this doubt, which had 
been raised in Dzierzon with regard to his own theory and by 
his own observations, as a sufficient reason for getting further in- 
formation from Herr von Berlepsch, who had obtained great 
experience in breeding Italian Bees for the last two years, with 
regard to the real truth in the production of hybrids taking place 
between Italian and German Bees. On the 2nd March of last 
year (1856) he replied to my questions put to him for this purpose, 
in the following manner. In the first place he referred to his 
observations already published in the BienenzeitungX, where he 
says : — " All queens which are of a beautiful yellow externally 
only produce Italian drones, even when they produce partly Italian 
and partly German workers. A German mother, which was 
fertilized by an Italian drone, produced German and Italian 
workers, hut only German drones. When on the contrary the 
mother is not of a fine yellow, — when she has traces of black blood 
in her, the drones also come forth mixed, whether the mother be 
fertilized by a German or Italian male : of course because the 

* See the Bienenzeitung , 1855, p. 79. 

t See the Bienenfreund aus Schlesien, ut cit. supra, p. 64. 

X For the year 1856, p. 6. 



IN THE HONEY-BEE. 75 

males only take after the mother." To this Von Berlepsch added 
the following commentary in his letter : — " An Italian queen fer- 
tilized by a German drone, or a German queen by an Italian 
drone, constantly (only one exception has occurred to me) pro- 
duces females (workers, queens) of three different colours: a. True 
Italians, that is to say, as yellow and banded as the female de- 
scendants of Italian queens, which were also fecundated by Italian 
drones ; b. True Germans, and c. Mongrels. With many mothers, 
the Italian, and with many the German descendants predominate; 
but the mongrels, which, as regards colour, are intermediate be- 
tween the Germans and Italians, are always in the minority, and 
indeed in the greatest minority, for in many hives we rarely see 
a mongrel, and in many none at all. Now as the queens are only 
workers, otherwise, that is to say, further developed, the same 
conditions occur in them also, and in hybrid mothers the colour 
of the royal descendants depends upon the egg. If the egg 
would have given a true Italian worker, it also furnishes a 
genuine Italian queen, &c. The males without exception follow 
the mother as regards colour, and during the last summer I was 
unable to discover with hybrid mothers even a single male which 
resembled its father, in spite of the most careful observation and 
the closest examination." 

After such important empirical facts, derived from the obser- 
vation of a great number of productions of hybrid Bees, it must 
therefore be regarded as certain, that, in accordance with Dzier- 
zon's theory, Bees of pure race are deprived of the power of pro- 
ducing hybrid drones. 

Notwithstanding the experiments hitherto made in a practical 
way, by which Dzierzon's theory has acquired the right of assert- 
ing its justice, we cannot reject the demand that, by means of direct 
experiments, we must acquire the conviction that the drone- eggs 
require no fertilization for their development, whilst the same eggs, 
in order to furnish female or worker-bees, must be fecundated-, 
for it is only by such strict scientific proofs that this new theory 
will acquire a firm and secure basis. 

Since the production of fishes by the artificial fecundation of 
the eggs had been carried on of late years with such fortunate 
results, it was natural to think whether it was not possible to 
establish the correctness of Dzierzon's theory incontrovertibly 



76 PARTHENOGENESIS 

by the artificial impregnation of the Bee's eggs. But this mode 
of proof was necessarily given up again at once as impracti- 
cable, for whoever submits the eggs of Bees to a close examina- 
tion will immediately see that these eggs, from their extreme 
delicacy, are quite unfitted for such experiments. There 
would be no possibility of extracting mature eggs uninjured 
from the ovaries, in order to transfer them either unfecundated 
or artificially impregnated into cells, to be taken care of by the 
Bees ; nor would these delicate eggs bear, without injury, 
the contact of a brush, however fine, moistened with the semen 
of male Bees, as would be required for artificial impregna- 
tion. Leuckart proposed* to employ eggs which had already 
been laid as drone-eggs in drone-cells, and to fertilize them arti- 
ficially afterwards, in order in this way to decide the question, 
whether we should succeed by artificial impregnation in deve- 
loping such eggs into workers or queens. He called atten- 
tion, however, at the same time, to the difficulties which are 
opposed to the success of this experiment. Leuckart justly 
pointed out, that only very fresh and newly deposited drone-eggs 
should be made use of for artificial fecundation ; for as soon as 
the thin albuminous coating, with which the eggs of insects are 
laid, becomes dry, which certainly takes place very quickly on 
deposited eggs, the semen employed for artificial impregnation 
can no longer penetrate through the pores of the egg-shell into 
the interior of the egg, by which means alone, as will be shown 
hereafter, the fertilization of the eggs of insects can be com- 
pleted. From the importance of the object which would be 
attained by these experiments, difficult as they are to carry out, 
1 heartily join in Leuckart' s wish, that such experiments should 
be undertaken by many hands ; perhaps one or other of the ex- 
perimenters would be so fortunate, by the concurrence of several 
favourable accidents, as to attain what from Dzierzon's theory 
must a priori be expected as the result. From the preceding 
statements it follows that the artificial impregnation of Bees' eggs 
could not as yet be employed in favour of Dzierzon's theory. 

Very different hopes were awakened in this respect, when we 
became acquainted with the existence and office of the micropyle 

* See the Bienenzeituny, 1855, p. 206. 



IN THE HONEY-BEE. 77 

of the eggs of insects. Since Leuckart and Meissner* have 
seen the spermatozoids penetrate the egg-shells through peculiar 
openings into the interior of the eggs of insects, we must say 
beforehand, that, if Dzierzon's theory proves to be correct, this 
process can only be observed in those eggs of Bees which are 
destined for the evolution of females or workers ; and that in the 

* I may be permitted, in reference to the discovery of this extremely import- 
ant and interesting phenomenon in the history of the fecundation of the eggs 
of animals, to mention the two names of Leuckart and Meissner; for according to 
epistolary communications upon this discovery, which I have in my hands from 
Meissner, I cannot but believe that both naturalists made their observations and 
discoveries on the eggs of insects independently of each other, and perhaps 
simultaneously. In a letter of the 8th of July 1854, which lies before me, 
Meissner writes from Gottingen : — " I have continued my observations upon 
fecundation, and indeed amongst insects. The result is briefly as follows : — 
In Diptera, Lepidoptera and Coleoptera, all the eggs have a micropyle at a 
definite spot, both in the chorion and vitelline membrane, and the spermatozoa 
penetrate from the seminal receptacle into the micropyle during the passage 
of the eggs through the vagina. In the Crustacea it is generally the same. 
I am still constantly occupied with investigations. In Musca vomitoria I 
found the still living spermatozoa in a mass, half in the yelk and half pro- 
truding from the micropyle. I am already busy with the elaboration of what 
I have found up to this time ; drawings are prepared, and in a few days I 
think of sending you the memoir to which I have just referred in a supple- 
ment to my last paper, and as a continuation of the latter." (See the Zeit- 
schrift fur wissenschaftliche Zoologie, band vi. p. 263.) These observations 
of Meissner's were printed in the 2nd heft of the Zeitschrift fur iviss. Zool. 
band vi. p. 272 (published on the 14th of September 1854). On the 17th of 
August 1854, at the Meeting of the Berlin Academy of Sciences, J. Muller 
read an epistolary communication, of the 12th of August in the same vear, 
from Professor Leuckart of Giessen, on the micropyle of the eggs of Insects 
(Bericht der Akad. der Wiss. zu Berlin, 1854, p. 494). This Report is pub- 
lished in separate monthly parts, of which the part for August had not vet 
reached me, when, on the 12th of October 1854, after my return from a vaca- 
tion-journey of two months to Munich, I wrote my letter to Herr von Ber- 
lepsch. Consequently when in this letter (see Bienenzeitung, 1854, p. 230) 
I only mentioned Meissner's observations upon the micropyle of the eggs of 
Insects, I was still unacquainted with the investigations which Leuckart had 
made, as he himself admits, almost simultaneously, in the same department of 
entomology. After this explanation, I think Leuckart has no longer any 
reason to reproach me with having ignored his investigations (see the Bienen- 
zeitung, 1855, p. 129, and Leuckart's memoir Ueber die Mikrupy/e und den 
feinern Ban der Schalenhaut hei den Insekteneiem, in Miiller's Archiv, 1855, 
p. 245). 



78 PARTHENOGENESIS 

eggs which remain unfecundated, from which only drones are 
developed, no spermatozoids will penetrate through the micro- 
pyle, whilst the micropylar apparatus must exist in exactly the 
same degree of development in all these eggs, as all eggs are 
originally of one and the same kind and nature. 

Those eggs of Bees which have to undergo a fertilization are 
fecundated at the moment when they slip past the orifice of the 
seminal duct of the receptacle within the oviduct (vagina). At 
this moment, as we may certainly suppose, some spermatozoa 
are pressed forth out of the efferent duct of the seminal receptacle, 
and these, in this way, by means of their mobility find an oppor- 
tunity of penetrating through the micropylar apparatus into the 
interior of the egg. That the act of fecundation of the insect- 
egg actually takes place at the point in the vagina just men- 
tioned, was asserted by me in the year 1837, and confirmed by 
an observation which I made upon Musca vomitoria*. In 
Musca vomitoria and its allies, which had not yet completed the 
business of oviposition, or perhaps had been disturbed in it, and 
had not immediately met with another suitable place for the 
deposition of their eggs, the eggs occurring in the ovarian tubes 
and in the oviduct differed in the following extremely interesting 
manner. The egg, which was fixed between the vulva and the 
orifice of the seminal receptacle, had already begun to develope 
itself, and contained an embryo ; whilst the egg found in the 
oviduct above the orifice of the seminal duct, which was per- 
fectly equal in size with the preceding one, did not betray a 
trace of the commencement of the development of the embryo, 
any more than the eggs contained in the Fallopian tubes. In 
such female Flies the seminal receptacle always contained mobile 
spermatozoa. At that time we contented ourselves, in the ex- 
planation of the process of fecundation, with the supposition that 
the contact of the spermatozoids sufficed to incite the egg to 
development; more recently we have been compelled to drop 
this theory of contact, since we have been able to trace the pene- 
tration of the spermatozoids into the interior of the egg. The 
process of impregnation will now have to be more precisely con- 
ceived in the following manner : — The fecundation and capability 

* See Muller's Archiv, 1837, p. 424. 



IN THE HONEY-BEE. J9 

of development of the egg are not produced merely by the imme- 
diate contact of the semen with the egg, but the elementary con- 
stituents of the semen, the mobile seminal filaments, must actually 
slip into the interior of the egg, very probably to become de- 
stroyed here at first, to be dissolved and then mixed with the 
elementary constituents of the egg*. For this purpose the eggs 
of insects possess a micropylar apparatus, that is to say, one or 
more small apertures at one of the poles, through which the 
spermatozoids must get into the interior as far as the yelk of the 
egg, in order to complete the act of fecundation. 

Leuckart was the first to set himself the task of ascertaining 
by direct observation, to what modifications the penetration 
of the spermatozoids through the micropylar apparatus of the 
eggs of the Bee would be subjected according to Dzierzon's 
theory. For this purpose he went to Seebach at the end of May 
last year, in order to be able to make use of the most abundant 
selection of the necessary objects for investigation. A better 
opportunity for such investigations could be presented to him 
nowhere else than in the immediate vicinity of the grand Bee- 
establishment at Seebach, in which however we must also take 
into account the disinterested liberality with which Herr von 
Berlepseh sacrificed his apiarian riches for the purposes of such 
physiological and anatomical investigations. 

Leuckart' s intention had already been announced by Berlepseh 
in the Bienenzeitungf, and I was therefore extremely anxious to 
know what results Leuckart would obtain from these Seebach 
studies. These have been recently published by Leuckart in the 
above-mentioned Journal, from which J I will here communicate 
the most important of the results. 

Leuckart was of course obliged in the first place to turn his 
particular attention to the micropylar apparatus of the eggs of 
Bees, of which he gave the following description § : — " As in the 
eggs of most insects, we distinguish in that of the Bees two 

* The cases of true Parthenogenesis are, of course, to be understood as 
forming the exceptions to this rule. 

t For 1855, p. 82. 2. 

% Bienenzeitung, 1855, Nos. 17 and 18 (published on the 30th of September), 
p. 99. Seebacher Studien. 

§ See loc. cit. supra, p. 204. 2. 



80 PARTHENOGENESIS 

membranes : an inner one, the so-called vitelline membrane, and 
an outer one, the egg-shell or the chorion. Both membranes 
are extremely thin and delicate : even the outer one, which other- 
wise (especially in those eggs which are deposited freely) is of 
considerable thickness and firmness ; the vitelline membrane is 
structureless, whilst the chorion is covered with a delicate hexa- 
gonal lattice- work, as with a network, as far as the hinder (lower) 
flattened end of the egg which serves for its attachment. The 
micropylar apparatus lies at the anterior or superior pole of the 
egg, which is the last excluded during oviposition (and after- 
wards contains the head of the young larva). At this point, 
where the ridges of the chorionic network run together, we see 
a little fan-shaped figure (of about y 1 ^ millim.) with about twelve 
rays. The rays of which the face is composed form the optical 
expression for the same number of micropylar canals, which run 
under the surface of the chorion. At their lower diverging ends 
these canals are open externally, whilst they open into the in- 
ternal space of the eggs with their opposite extremities. The 
structure is exactly the same as in a number of other Hymeno- 
ptera (see M tiller's Archiv, 1855, p. 236. taf. 11. figs. 12, 13), 
but with this distinction, that in this case the micropylar canals 
are most extraordinarily thin and delicate ; so that we can hardly 
convince ourselves with certainty of their real nature, and at the 
first glance might almost be inclined to regard the rays as ridges, 
such as also occur on the other parts of the chorion. The canals 
can hardly be more than j qV o m il nm - m diameter, certainly still 
sufficient to allow the passage of a seminal filament. During 
the last period of its stay in the ovary, the Bee's egg receives 
another external coating of an albuminous nature, which indeed 
is reduced to almost nothing on the anterior (superior) half, but 
gradually thickens posteriorly, and acquires a very considerable 
development at the flattened posterior (inferior) pole. This 
albuminous deposit serves for the attachment of the egg to the 
wall of the cell/' Although I do not quite agree with this 
Leuckartian conception of the micropylar apparatus of the Bee's 
eggs, and I am especially compelled to regard the above-mentioned 
micropylar canals as something else, a detailed criticism of this 
representation of Leuckart's would lead me too far, and 1 there- 
fore reserve this for another occasion, and will make use of the 



IN THE HONEY-BEE. M 

expression micropylar apparatus, without connecting therewith 
exactly the same idea as that which has been formed of it by 
Leuckart. The possibility of success in the above-mentioned 
(p. 76) artificial impregnation must depend, as Leuckart has 
very justly observed*, upon the thin albuminous coat of the eggs 
of Bees, for as soon as this albuminous coat has dried, which 
will certainly be the case within a few minutes of the deposition 
of the eggs in the waxen cells, the orifices of the micropylar ap- 
paratus will be plastered over with it, so that the seminal fila- 
ments will be prevented from penetrating into the interior of 
the egg. 

Leuckart's statement alsof, that it is impossible, from the 
external condition of the Bee's egg, to arrive at any conclusion 
as to the sex of the Bee which is to be developed in it, is im- 
portant, and I can fully confirm it. 

Leuckart now hoped J " by the assistance of the microscope 
to ascertain the presence or absence of the seminal filaments 
upon the micropylar apparatus of freshly-deposited drone-eggs, 
and from this to draw a conclusion as to their fecundation or 
non-fecundation/' as he knew " that in many cases it is not 
difficult to discover the seminal filaments singly or in strings, 
sometimes even in very considerable ones, in the albuminous layer 
covering the micropyle in freshly-laid eggs, and even to witness 
the act of slipping in through the micropyle." Unfortunately 
these hopes were not fulfilled, for Leuckart was compelled to 
admit that what he observed is not sufficient for the decision 
of the question, and only possesses some value in as far as 
Dzierzon's hypothesis is not directly contradicted by it. 

Leuckart accounts for the failure of his design as follows J : — 
"The Bee is one of those insects which in fecundation only 
deposit very few seminal filaments, perhaps in many cases only a 
single one, upon their eggs. Important and significant as this 
circumstance is for the practical breeding of Bees, as only by it 
does it become possible that the queen, notwithstanding her 
immense fertility, can lay eggs for years together without ex- 
hausting the contents of her seminal receptacle — it is evident 
that it is equally unfavourable and unwelcome to the physio- 

* See Seebocher Studien, loc. cit. supra, p. 206. 1 . 
t Loc. cit. p. 204. 1. X Loc cit. p. 20;"). 1. 



82 PARTHENOGENESIS 

logist who is in search of these filaments. To this we may 
further add, that in Bees' eggs the seminal filaments have not to 
penetrate through a thick albuminous layer before reaching the 
chorion, as is so frequently the case in other insects, but that 
they are deposited almost immediately upon the micropylar 
apparatus, and consequently can penetrate through its canals in 
a very short time. Lastly, if we consider the difficulties which 
are thrown in the way of the microscopic preparation of the 
Bee's egg by the great elasticity and the delicate texture of the 
chorion, we can hardly complain of an observer if he has not 
arrived at any satisfactory result in this case. I admit freely, 
that the investigation of the Bee's egg has been the most diffi- 
cult of all the numerous investigations of this kind which I have 
undertaken during the last two summers." 

By an unlucky chance, Leuckart whilst in Seebach found 
no opportunity of examining perfectly fresh-laid Bees' eggs, 
and at the time when Leuckart undertook these investigations, 
Von Berlepsch could by no means bring a queen to deposit 
her eggs. As the result of these Seebach studies, therefore, 
Leuckart could only furnish the editor of the Bienenzeitung 
with the following information : — " But you wish, then, to 
know to what my investigations have led in general? I reply 
that on two occasions only I met with some undoubted seminal 
filaments upon the micropyle of Bees' eggs ; on one occasion a 
single filament, on the other several, four or five (and yet I have 
most carefully examined more than fifty Bees' eggs !). On both 
occasions it was upon worker-eggs that I found the seminal 
filaments. In drone-eggs I have never been able to distinguish 
a seminal filament, although I probably examined more drone- 
eggs than worker-eggs, and amongst these such as had been laid 
at the utmost a quarter of an hour previously. You see, the 
result is doubtful. At all events it appears rather to speak in 
favour of, than against, Dzierzon ; but I must again repeat that 
this appearance is possibly deceptive. In the interest of science, 
it would delight me exceedingly if other observers should be 
more fortunate than I have been in this respect." 

For the satisfaction of Leuckart I may state here, that I have 
actually been more fortunate than him, and that I have seen 
what his eyes did not succeed in beholding. " Until " (so 



IN THE HONEY-BEE. S.3 

Leuckart closes his statements* relating to this subject), "either 
by experiment or by direct observation, the strict proof is 
obtained, that it is only the eggs of the female Bees that are 
impregnated, the question as to the causality of sex in the Bees 
remains an open one. Theoretical and other reasons may 
henceforth induce us either to support or oppose Dzierzon, 
and we may increase the materials for the settlement of this 
question in an indirect way — its decision cannot possibly be 
brought about thereby." I have in fact been able to furnish by 
direct observation that evidence which must have been required 
by science as alone sufficient for the establishment of Dzierzon's 
theory. How far I may consider myself justified in this asser- 
tion, may be ascertained from the following statements : — 

Although I knew that Leuckart was about to commence the 
above-mentioned investigations at Seebach, I had also long before 
undertaken to make similar investigations in the interest of 
science. Without knowing that Leuckart had already carried out 
his Seebach studies, and without being acquainted with the 
results which he had obtained from them, I also went to Seebach 
in the middle of August last year, because I was convinced 
that such investigations could only be undertaken by the aid of 
the abundant materials which would there stand at my command 
by the acknowledged complaisance of Herr von Berlepsch ; I 
certainly entertained but little hope of attaining my end, as 
the season of the year was already too far advanced for such 
investigations. On the 21st of August I was received by Herr 
von Berlepsch with the assurance, calculated to inspire very little 
courage, that I would probably find it difficult to meet with the 
necessary material, which I required for my investigations, at 
so late a period of the summer, and therefore that I had little 
chance of solving the problem before me, especially as Leuckart 
had been here at Whitsuntide, and therefore at a more favourable 
season of the year, but had departed without attaining his object, 
and confessed to Von Berlepsch that the questions relating 
to Dzierzon's theory could not be solved by the microscope on 
account of the very great difficulties which were to be overcome 
in the investigations to be made for that purpose. Nevertheless, 

* Loc. cit. supra, p. 206. 2. 

G 2 



84 PARTHENOGENESIS 

I did not allow myself to be deterred from entering upon these 
investigations. 

I was, however, actually astonished at the Bee-material which 
offered itself to me in Seebach, for the masses of Bee-colonies, 
as well as their judicious arrangement, so favourable to observa- 
tions of every kind, surpassed all my expectations. I found 
104 Dzierzon hives overflowing with honey and bees, destined 
for hybernation, and indeed distributed in various ways in eight 
places in a spacious orchard, amongst which I was particularly 
surprised at the pavilion containing 28 bee-hives, already 
frequently referred to in the Bienenzeitung. The distance of 
these eight Bee-establishments from each other was never more 
than 40 feet Rhenish. Amongst these hives there were nine 
genuine Italian colonies of Bees, the number of which might 
have been much greater, if, as Herr von Berlepsch asserted, 
seventy Italian mothers had not been furnished by him to other 
Bee-keepers, and the hives generally very much prejudiced by 
the various scientific experiments*. What has been of particu- 
lar service to Von Berlepsch in his Bee-keeping is the assistance 
of his servant Giinther, who, being endowed with excellent 
talents, has been instructed by Berlepsch himself in the mystery 
of Bee-keeping, and has approved himself in a distinguished 
manner j*. 

I immediately set to work and examined a great number of 
female eggs, with which the great Bee-establishment of Herr 
von Berlepsch still furnished me in large quantities. It first 
occurred to me to make myself well acquainted with the organi- 

t What advantages may be obtained with the assistance of Dzierzon's hives, 
by assiduity and attention, and especially by the proper comprehension of the 
mode of life of Bees, will be seen by the dexterity with which Herr von 
Berlepsch manages his bee-hives even in a district which is poor in honey, as 
Seebach is described by himself (see bienenzeitung, 1855, p. 3). According to 
Berlepsch's assertion, every one of his hives would be capable of giving him 
annually 30 pounds of honey and \\ pound of wax, according to which 3120 
pounds of honey and 130 pounds of wax, of the value of fully 400 dollars, 
might accrue to him from the whole 104 hives. 

* This excellent assistant, who, as his master asserts, and I can testify, 
may be placed beside Huber's servant, Francois Burnens (see F. Huber, Nou- 
velles Observ.), has unfortunately been compelled to leave Seebach for the 
present, to pass his years of military service. 



IN THE HONEY-BEE. 85 

zation of the eggs of Bees, so as to be exposed to no delusions 
or errors subsequently in seeking for the spermatozoids. It was 
only after I had exactly ascertained the structure of the egg- 
envelopes, the micropylar apparatus and the yelk, and practised 
myself in the preparation of the eggs of Bees, that I turned my 
attention to the spermatozoids, by whose presence or absence 
the principal decision was to be given. Above all, the most 
exact acquaintance was required with the individual ridges of 
the lattice-work of the egg-shell, which is composed of irregular 
hexagons, as well as with the folds of the vitelline membrane 
accidentally produced during examination, so as not to confound 
these things with spermatozoids which had become motionless. 
After I had, in this way, made myself sufficiently familiar with 
the examination of the eggs of Bees, I had a comb brought to 
me at 10 o'clock in the morning of the 22nd of August, contain- 
ing female eggs, which had been deposited at the utmost an hour 
before. I might expect beforehand that no trace of spermato- 
zoids would be recognizable externally in these eggs ; I there- 
fore directed all my attention to their contents, and hoped to 
discover the spermatozoids which had already penetrated through 
the micropyle, in the interior of the eggs. I soon convinced 
myself that there was no possibility of discovering the delicate 
seminal filaments between the granulo-vesicular yelk-masses ; the 
linear object to be sought for was too subtile to be capable of 
discovery with certainty amongst the many mutually-crossing 
outlines of the yelk-vesicles. After various vain endeavours to 
render the interior of the Bee's egg accessible to the inquiring 
eye, I came at last to the idea of employing an artifice, which I 
had soon acquired by practice, and which allowed me to survey 
at least a portion of the inner space of the Bee's eggs with great 
clearness and tranquillity. I crushed a Bee's egg quite gently 
with a very thin glass -plate, and so that it was ruptured at its 
lower pole, opposite to the micropylar apparatus, and the yelk 
gradually flowed out at this spot, by which a clear empty space 
was produced at the upper pole within the micropylar apparatus, 
between the egg- envelopes and the yelk which was retiring 
downwards. I directed my attention very particularly to this 
empty space, which I saw slowly produced under the microscope 
during the effusion of the yelk. The production of such a pre- 



86 PARTHENOGENESIS 

paration of course was not always successful, for sometimes the 
yelk flowed out of the ruptured envelopes, without the produc- 
tion of this empty space ; the yelk also remained diffused in the 
upper part, and allowed of no certain judgment as to the pre- 
sence or absence of seminal filaments. An error in crushing the 
egg, a little too much pressure upon it, or perhaps also a pecu- 
liar, less tenacious consistency of the yelk, probably caused the 
contents of the yelk to retire in every direction from the pressure, 
and therefore also to press upwards against the micropylar 
apparatus. 

From the above-mentioned comb I examined ten eggs, which 
T succeeded in transferring uninjured from their cells upon an 
object-glass, which, from the delicacy of these eggs, is always a 
matter of difficulty. The result of their microscopic examina- 
tion was as follows : — 

The first female egg exhibited nothing remarkable. In the 
interior of the second egg, to my great delight, I observed three 
distinct, but motionless seminal filaments within the empty 
space which had been produced at the superior pole of the egg 
by the flowing out of the yelk through the inferior pole. In a 
third egg, after the same retirement of the yelk, I saw, in the 
superior space of the egg which had become empty, a single 
motionless seminal filament. In a fourth egg, I again observed 
three motionless seminal filaments at the same spot. A fifth 
egg, prepared in the same way, exhibited no seminal filaments. 
A sixth and a seventh had probably been too strongly squeezed 
in their preparation ; the necessary empty space could not be 
produced in the interior of the egg at its superior pole, for which 
reason I regarded these preparations as of no use for investiga- 
tion. In an eighth and ninth egg, fortunately prepared, I again 
saw a single motionless seminal filament in the superior empty 
space of the cavity of the egg. In the tenth egg the preparation 
was quite unsuccessful. This same comb with female eggs, after 
being carefully preserved in a room, was made use of for the 
continuation of these investigations at 8 o'clock in the morning 
of the 23rd of August. An eleventh egg was spoilt during the 
preparation ; as was also a twelfth. A thirteenth egg was in an 
extremely interesting condition. After it had been for twenty- 
two hours out of the bee-hive and had been successfully pre- 



IN THE HONEY-BEE. 87 

pared in the way above described, it exhibited two spermatozoids 
in the clear empty space between the egg-membranes and the 
yelk which had retired on the crushing of the egg. One of the 
seminal filaments performed very lively tortuous movements ; the 
second filament was rigid, but adhered firmly to the other 
seminal filament, and was thus moved by its movements. These 
movements were first seen by me at about half-past eight, and 
were also observed by Von Berlepsch and Giinther and by two 
other witnesses. Three minutes afterwards the seminal filament 
was still active. The preparation was then put by, and not again 
examined under the microscope for fifteen minutes. The move- 
ments of the first seminal filament had then ceased also, but 
both spermatozoids, although motionless, were still clearly di- 
stinguishable in the same spot. A fourteenth egg furnished no 
result, its preparation being unsuccessful. In a fifteenth, four 
distinct but motionless spermatozoids were discoverable in the 
space which had become empty during the preparation, between 
the envelopes and the retreating yelk. 

On the same day, another comb with female eggs was removed 
from another bee-hive ; it might at the utmost have been twelve 
hours old. The investigations continued with these eggs gave 
the following results. A sixteenth egg, the preparation of which 
turned out well, exhibited no seminal filaments in its interior. 
With the seventeenth egg the preparation was unsuccessful. 
An eighteenth egg contained three seminal filaments in the spot 
above mentioned; one of these was active. In the nineteenth 
and twentieth eggs the preparation was unsuccessful. The 
twenty-first contained two motionless seminal filaments, as did 
also the twenty-second. In the twenty-third egg, on the con- 
trary, I could distinguish four motionless seminal filaments. 
With the twenty-fourth and twenty-fifth eggs the preparation 
was unsuccessful. The twenty-sixth and twenty- seventh again 
exhibited a single motionless filament, and the twenty-eighth 
two of them. The four following eggs all showed only a single 
motionless seminal filament. The examination of the thirty- 
third egg was again unsuccessful. The thirty-fourth and thirty- 
fifth eggs exhibited three motionless spermatozoids, and the 
thirty-sixth egg examined by me contained one active and three 
motionless seminal filaments. In the thirty-seventh and thirty- 



88 PARTHENOGENESIS 

eighth eggs I could only perceive a motionless spermatozoid ; in 
the thirty-ninth, fortieth and forty-first, on the contrary, I was 
able to discover two rigid spermatozoids. 

On the 23rd of August a third comb furnished with female 
eggs was also employed for investigation, the eggs in which 
had only just been deposited. These eggs, however, did not 
show themselves so favourable to the above-described mode 
of investigation employed by me, because the yelk would 
not detach itself so easily from the vitelline membrane after 
the rupture of the envelopes; w 7 here I succeeded in pro- 
ducing the empty space between the envelopes of the egg 
and the yelk in these eggs, I often found it possible to dis- 
cover spermatozoids in their interior. Not to weary the reader, 
I will only enumerate a portion of these investigations in their 
order : — The forty-third egg allowed a motionless seminal fila- 
ment to be detected, sitting externally upon the micropylar 
apparatus. The forty-fourth and forty- fifth eggs furnished no 
results, from unsuccessful preparation. The examination of these 
was not repeated until seven o'clock in the morning of the 
24th of August, when these deposited eggs were fifteen hours 
old. The forty-sixth egg contained several coiled but motionless 
spermatozoids. In the forty-seventh egg I was able to discover 
one motionless seminal filament ; with the forty-eighth the pre- 
paration was unsuccessful, and with the forty- ninth and fiftieth 
I was obliged to leave it doubtful whether the object which 
might have been taken for a seminal filament, was such in 
reality. Both the fifty-first and fifty-second eggs allowed a 
motionless seminal filament to be clearly distinguished in the 
empty space, when the yeik had retracted itself downwards from 
the micropylar apparatus by the rupture of the egg-shells. 

If I sum up the observations just referred to, they furnish 
on the whole a very favourable result, considering the difficulties 
of the investigation, for I have also convinced myself, that these 
investigations of the egg of the Bee, are, as Leuckart has very 
justly asserted*, amongst the most difficult of all investigations 
of the kind. Amongst the fifty-two female Bee-eggs examined 
by me with the greatest care and conscientiousness, thirty fur- 
nished a positive result; that is to say, in thirty, I could prove 
* Sec his Seebacher Studien in the Bienenzeitimy, 1855, p. 205. 2. 



IN THE HONEY-BEE. 89 

the existence of seminal filaments, in which movements could 
even be detected in three eggs. Of the other twenty -two eggs, 
twelve were unsuccessful in their preparation. At the same time 
I may also indicate particularly, that the observations with posi- 
tive and negative results followed each other quite irregularly, 
but alternating at very short intervals, which probably was only 
dependent upon the favourable or unfavourable consequences of 
my preparation of the eggs employed for observation. If the 
question is to be raised, why Leuckart was not so fortunate as 
to see what I have succeeded in seeing, I can make no other 
answer, but that probably the different method followed by us 
in our investigations, is to be blamed for Leuckart's want of 
success. Berlepsch informed me, that Leuckart did not exa- 
mine the contents of the eggs by the careful compression of the 
Bee's egg, but that he confined himself to submitting the eggs 
in a perfectly uninjured state to an external examination. 

It is certainly to my mode of investigation alone that I am 
indebted for the successful result of these observations, which 
were made with an excellent microscope of Kellner's. The 
careful rupture of the egg- membrane effected always by me, 
must prove an extremely important manipulation, for by this 
alone was it possible evidently to isolate the delicate seminal 
filaments w T hich had penetrated into the cavity of the egg and 
become concealed by the yelk-mass, as, after penetrating into 
the egg they probably continue adhering for some time to the 
micropylar apparatus by their caudal extremity and remain 
behind, isolated in the upper empty portion of the cavity of the 
egg during the issue of the yelk-mass after the rupture of the 
membranes. 

Above all things, however, it was of consequence to me that 
I should be able to examine male eggs (drone-eggs) also in 
exactly the same way, and Herr von Berlepsch actually pro- 
cured me the means of doing this, although at first he had given 
me but little hope of obtaining such drone-eggs even in small 
number. It was truly a chef-d'oeuvre to obtain drone-eggs at so 
late a season : how my acute and experienced friend as it were 
compelled a queen to lay male eggs, the reader will be able to 
understand from what follows. 

In No. 7^ of his Bee-hives, Herr von Berlepsch possessed a 



90 PARTHENOGENESIS 

queen, which he knew to be near her death, as her Bees had 
been constantly constructing royal-cells since the end of June, 
and the queen furnished these with eggs by which her loss 
might be replaced. Berlepsch, however, had not permitted the 
larvae in these cells to come to exclusion, and thus this aged 
mother was still alive when I arrived at Seebach and inquired for 
drone-eggs. A little while before, this queen had laid drone- 
eggs, but Berlepsch had destroyed this drone-brood also, as being 
useless. At last the workers had enough of it, and commenced 
no more cells. Berlepscrr's object in this case was to determine 
how long the life of a queen might be prolonged artificially. 
When I came to Seebach, this queen was still laying single 
eggs. On the 21st of August Giinther received the charge to 
feed the hive, No. 79> in the evening with fluid honey ; the next 
evening (22nd of August) two combs with covered worker-brood, 
and between the two an empty drone-comb, were suspended in 
this hive. The following morning (23rd of August) there were 
twenty-seven drone-eggs in this drone-comb, and about sixty 
worker-eggs in open cells of the worker-combs. Berlepsch had 
carefully ascertained previously that not a single egg was present 
in the open cells of both the foreign worker-combs, when sus- 
pended in the experimental hive. 

I examined these twenty-seven drone-eggs, which might have 
been about twelve hours old, and which agreed perfectly both in 
their appearance and organization with the female eggs, with the 
same care and by the same method with which I had treated 
the female eggs, and did not find one seminal filament in any 
single egg, either externally or internally. I must also add, that 
only the seventh, thirteenth and twenty-third eggs were unsuc- 
cessfully prepared. In all the rest of these drone-eggs the yelk 
retreated slowly and completely from the upper pole of the 
egg-envelopes, after the bursting of the membranes ; the desired 
empty clear space between the micropylar apparatus and the 
retreating yelk was produced in the interior of these eggs, so 
that if seminal filaments had been present in them, they cer- 
tainly would not have escaped my searching and inquisitive eye. 
In order to be quite satisfied as to this remarkable negative 
result, and to obtain the full signification of it, several female 
eggs of the same queen which had furnished these drone-eggs, 



IN THE HONEY-BEE. . 91 

were examined for comparison ; for the objection might certainly 
have been raised, that this queen might have laid nothing but 
barren eggs, as, being already weakened by age and near her 
death, she might have had no more sperm atozoids in her seminal 
receptacle. Nevertheless, many of these eggs contained seminal 
filaments ; they were the twenty-seven eggs already mentioned 
by me, — namely the sixteenth to the forty-second eggs. 

To this result of my Seebach investigations, which proves the 
correctness of Dzierzon's theory by direct observations, I may 
also add that Herr von Berlepsch has lately informed me by 
letter, that this queen subsequently, after my departure from 
Seebach, also laid female eggs, from which workers were deve- 
loped, but she herself only died on the 19th September, 1855. 



92 



TRUE PARTHENOGENESIS IN THE SILK-WORM MOTH. 

Having proved the occurrence of a true Parthenogenesis, com- 
bined with such extremely remarkable phenomena, in the Bees, 
I return once more to the Lepidoptera, in order to refer to the 
Bombyx Mori, regarding which notices were constantly coming 
to my ears, sometimes here, sometimes there, which indicated 
the Silk-worm Moth as one which sometimes laid eggs capable 
of development sine concubitu. The older statements relating 
to this appeared to me at first to be equally unfounded with 
the other cases of Parthenogenesis in the moths elucidated by 
me (p. 12). 

How little inclination there was even formerly to believe in 
any such Parthenogenesis of the Silk- worm, appears from a letter 
written by Constans de Castellet, General Inspector of the Silk 
establishments in the kingdom of Sardinia, in which* he reports 
that eleven female silk-worm moths which had just crept out of 
the cocoon were observed by him, which, in their virgin state, 
deposited eggs, from which caterpillars and cocoons were 
reared. Castellet, who had not expected this, and wished to be 
sure that he had not deceived himself, repeated the experiment, 
imprisoned the female cocoons in different rooms, and convinced 
himself of the thriving of the silk-worms which he afterwards 
obtained from the virgin brood deposited by these moths. He 
made a report upon this case to Reaumur, who however an- 
swered him shortly : ex nihilo nihil fit, and doubted the cor- 
rectness of the facts. By such an answer from so distinguished 
a naturalist, Castellet found himself induced to investigate the 
affair closely once more, and believed that he had at last got at 
the reason of it, by thinking that he saw that silk-worms in his 
breeding-place, which were already very near the time for spin- 
ning themselves up, had copulated. He thought he observed, 

* See the letter referred to : Sulle uova de* vermi da seta fecondate senza 
V accoppiamento delle farfalle, in the Opuscoli Scelti sidle scienze et sidle arti, 
torn, xviii. 17^5, p. 242. 



PARTHENOGENESIS IN THE SILK-WORM. 93 

namely, that some caterpillars had united quickly and others 
more slowly for a moment with the hinder extremity of their 
body. What is to be thought of this observed union, may be 
left to every one who is acquainted with the anatomical con- 
struction of an adult caterpillar, as regards the generative 
organs. 

A later notice relating to this subject is the assertion of 
Herold, according to which*, amongst the eggs of an unferti- 
lized silk-worm moth, some here and there are said to have 
passed wholly or partially through the same changes which are 
observed in eggs fertilized by true copulation, whilst most of 
the eggs remained unaltered. Herold, in his representation of 
the development of the egg of the silk-worm moth, even di- 
stinguishes between foetuses developed from fecundated and un- 
fecundated eggs, of which the former make their escape, whilst 
the latter always remain in the egg-shell and dief. Although 
Herold has not stated more precisely what precautions he took 
to attain the certain conviction that the brood produced from 
unfertilized eggs was actually derived from virgin females, I 
nevertheless looked upon the above assertion of Herold with 
less distrust than upon the before-mentioned examples of sup- 
posed Parthenogenesis derived from the history of reproduction 
of the moths, as with the very sluggish silk-worm moths, which 
do not fly about in the open air, there could be much less 
probability of the occurrence of a secret and unobserved copu- 
lation. 

It is remarkable that this spontaneous evolution of the embryo 
in unfecundated eggs, mentioned byHerold, an observation which 
might easily be repeated upon the Silk-worms, which are so 
widely diffused, has hitherto escaped the attention of physio- 
logists. Herold was the first who furnished an exact and de- 
tailed description of those changes which may be detected with 
the lens in a determinate sequence in different silk-worm eggs 
developing themselves without fecundation. He described first 
of all, upon the sixth plate of his Disquisitiones^, the consecutive 

* Disquisitiones de animalium vertebris carentium in ovo format ion e. 
Fasc. ii. 1838, tab. 7- 

T hoc. cit. tab. 7- fig. 31. 

J Disquisitiones, &c. Fasc. ii. 1838. 



94 PARTHENOGENESIS 

changes which the silk- worm eggs rendered capable of deve- 
lopment by a fertile copulation undergo with regard to their 
outline, colour and contents, from the moment of deposition up 
to that condition in which they remain more or less unaltered 
through the whole winter. He also points out particularly that 
the coloured membrane which makes its appearance below the 
egg-shell, and which passes through a definite change of colour, 
upon which the changes of colour of the whole egg depend, 
is certainly in general a sure indication that fecundation has 
taken place, but especially the most certain token that the eggs 
are actually capable of development. Herold at the same time 
figures an embryo * as it occurs in the middle of winter in the 
fecundated egg of a silk-worm moth, after the egg has completed 
its change of colour within the first eight or ten days after depo- 
sition. On the seventh plate Herold represents the consecutive 
changes " in regard to outline, colour and contents undergone, 
in the first weeks after deposition, up to the state in which 
they remain more or less unaltered throughout the winter, by 
many of the eggs which the female silk- worm moth lays by her- 
self, without copulation with the male, and many of which are 
nevertheless endowed in different degrees with the power of de- 
velopment almost like those which are actually rendered fertile 
by the assistance of the male." He could distinguish various 
degrees of the faculty of development of unfertilized eggs, which 
manifested themselves by infinite differences in the disposition, 
number, form, and strength of colour, of the coloured parts of 
the egg. In some of these unfecundated eggs the faculty of 
development had attained such a high degree, that Herold was 
able to extract a foetus from one of them in the middle of winterf. 
According to Herold's further statements, however, embryos 
were not found in all unfertilized eggs capable of development 
which he examined in the winter, and he had also never seen 
young caterpillars creep out of unfertilized eggs, as they had 
previously ceased to live. 

Moreover, Malpighi was already acquainted with the distinc- 
tion between fertilized and unfertilized silk-worm eggs. This 
distinguished naturalist long since knew, what has been left un- 

* hoc. cit. sup. tab. 6. fig. 15. t hoc. cit. tab. 7- fig- 19. 



IN THE SILK-WORM MOTH. 95 

noticed by a later physiological school, namely that the ovaries 
were not fertilized by copulation, but that after a copulation each 
individual ready-formed egg is fertilized for itself. This appears 
distinctly from his published investigations. Malpighi saw* 
that the sulphur-yellow eggs taken out of the ovaries of a fecun- 
dated silk-worm moth behaved exactly like unfecundated eggs ; 
whilst an egg, which he discovered in the vagina of this moth, 
acquired a violet colour in course of time, and consequently 
showed itself to be fecundated. Malpighi derived this influence 
from the contents of the bursa copulatrix, the signification of 
which and its opening into the vagina he knewf. The seminal 
receptacle also certainly had not escaped his searching glance, 
but he had not comprehended its importance J. Pallas § also 
referred to the changes of colour undergone by the fertilized eggs 
of the silk-worm moth and other moths after they have been laid. 
He observed that the eggs of a Papilio Iris, which he cut out of 
the body of a fecundated female, did not change their grass-green 
colour, whilst the deposited eggs of a fertilized butterfly of this 
kind became yellowish-green ; and from this he drew the correct 
conclusion, that the fertilization of these eggs only takes place 
during their passage through the vagina of the mother (see Note 
on Hunter's experiments at p. 52). 

Exactly at the time when I had become acquainted with the 
Parthenogenesis of the Psychidce, my attention was called from 
several sides to the occurrence of Parthenogenesis in Bombyx 
Mori, in such a way that I could not avoid a closer examination 
of the phaenomena here referred to. 

The principal incitement to this was furnished by the following 
statement, made in the year 1851 by P. de' Filippi|| : — " Je me 
bornerai a citer un cas singulier, qui m'a ete raconte tout 
dernierement par un celebre entomologiste anglais, M. John 
Curtis, a son passage par Turin, d'une chrysalide isolee de 
Bombyx poly phemus qu'il avait recue de l'Amerique, et de laquelle 

* Marc. Malpighii Dissertatio de Bombyce, Londini, 1669, p. 82. 
t Op. cit. p. 81. tab. 12. fig. 1. K, I, M. 
% Op. cit. p. 80. tab. 12. fig. 1. E, F, G, H. 

§ See his Anmerkungen uber einige Besonderheiten an Insekten, in the 
Stralsunder Magazin, band i. st. 3. 1768, p. 240. 

\\ See Annates des Sciences Naturelles, Zootogie, torn. v. 1861, p. 2!>7. 



96 PARTHENOGENESIS 

naquit une femelle dont tous les ceufs se developperent. Je crois 
que la meme chose a lieu quelquefois dans les femelles de Bom- 
byx Mori, quoique tout a fait separees des males." 

This notice brought to my mind several other communications 
as to the possibility of a Parthenogenesis in Bombyx Mori, upon 
which I was now compelled to lay the greater stress, after Filippi, 
whom I knew to be a thoroughly cautious physiologist, had come 
forward as a witness to the correctness of this assertiun. I re- 
called to mind a statement of Mogling's*, that the female moth 
of Bombyx Mori lays 350 to 480 eggs, which might be capable 
of development although the female was not fertilized by any 
malet- Here also evidently belongs that observation of Bour- 
sier's which was reported some years ago in the Comptes Rendus%, 
that a female silk-worm moth, which had not copulated with a 
male, had been exposed by Boursier, sometimes to the sun and 
sometimes to the shade, during which treatment the moth laid 
many eggs, of which those which were laid in the sun furnished 
caterpillars. Although no one will attribute the fertilization of 
the eggs in the preceding case, as Boursier has done, to the in- 
fluence of the light and heat of the sun, we shall not be able to 
help seeing a Parthenogenesis in this phenomenon. I applied 
to Filippi himself, in order to obtain something further from 
him as to the propagation of the silk-worm moth sine concubitu, 
as he lives in a country in which the cultivation of silk is carried 
on to a very great extent ; and he certainly could easily have 
collected observations upon the subject in question. Filippi 
wrote to me on the 29th of May 1852, as follows : — " Quant aux 
oeufs de Bombyx Mori eclos sans fecondation prealable, voila ce 
que je pourrais ajouter. C'est en 1850 que j'ai eu occasion 
d'observer une chose pareille avec des vers a soie de la variete 
dite parmi nous des trevoltini (c^est a dire qui peuvent etre 
eleves trois fois dans l'annee). Aussi M. Griseri, qui s'occupe 
beaucoup de ^education des vers a soie, a trouve que plusieurs 

* See his book upon the Silk-worm, 184/, p. 89. 

t Moslins here refers to the Notices sur les Educations des Vers a Soie 
faites en 1840 par M. Robinet, which have not yet come under my notice. 

X See Comptes Rendus, No. 12. 1847, or Notizen von Schleiden und Froriep, 
band v. 1848, p. 20. 



IN THE SILK-WORM MOTH. 97 

oeufs deposes par des femelles vierges se developpent. Plusieurs 
cultivateurs de vers a soie m'ont assures la meme chose." 

These various notices upon Bombyx Mori, taken together with 
the observation made by Curtis upon an isolated American 
Bombyx, in which no mistake could certainly have slipped in, 
as well as an observation reported by Johnston *, according to 
which caterpillars were evolved from the eggs taken out of the 
body, and therefore unfecundated, of a Smerinthus ocellatus 
killed two days previously, — all these statements confirmed me in 
supposing the existence of a Parthenogenesis also in Bombyx 
Mori, although I have denied this amongst the Lepidoptera, with 
the exception of particular Psychidce. I am not on this account 
to be accused of an inconsistency, for the examples previously 
(p. 12) cited by me, which were supposed to speak in favour of 
the Parthenogenesis of the moths, can never be admitted as 
credible evidence, for the reasons already asserted. 

In order to obtain personal observations upon the Partheno- 
genesis in Bombyx Mori, I put myself in communication with 
various silk-worm breeders in Breslau and Munich ; from these 
also I received the serious assurance, that caterpillars were not un- 
frequently developed from the eggs laid by unfertilized female silk- 
worm moths. By the courtesy of the manufacturer, Herr Steiner 
of Breslau, an extensive silk-breeding establishment was put at 
my disposal, with the aid of which I was enabled to inform my- 
self upon various interesting processes in the oviposition and 
development of the Silk-worm. First of all, in the summer of 
1852, I procured a sufficient number of silk cocoons of male and 
female sex. After their exclusion, I allowed several pairs to 
copulate, whilst I strictly separated and watched another quan- 
tity of female moths, which I had already recognized as such in 
the cocoons. Both the fertilized females and those which had 
remained unfertilized, of which I had selected seven for observa- 
tion, deposited a great quantity of eggs, all of which I submitted 
to a very careful inspection. Almost all the eggs laid by the 

* See the Zoologist, 1848, p. 2269, and also Schleiden und Froricp's Xo- 
tizen, 1849, band viii. p. 170- I presuppose that in the present case the eggs 
were taken out of the ovaries, and not out of the oviduct, because otherwise, 
after any preliminary copulation, such eggs might have been fecundated from 
the seminal receptacle. 

H 



9S PARTHENOGENESIS 

fecundated silk-worm moths changed in a few days in the well- 
known manner, their sulphur-yellow colour gradually becoming 
converted into dark yellow, then into orange, red, violet, and lastly 
into bluish or slaty-grey, which had often taken place even on the 
third day after laying. The eggs at the same time remained 
tense, and bore in their middle the flat impression which is also 
well known. In this bluish colour, as the token of their vitality, 
I got these eggs through the winter, and in the following spring 
they furnished me with a great number of caterpillars. I must 
here observe, that the previously mentioned change of colour of the 
Silk- worm's egg does not arise from a commencement of the deve- 
lopment of the embryo, but is only the consequence of a peculiar 
alteration of the yelk, which at first shines through the colour- 
less, dimly transparent egg-shell with a sulphur-yellow colour, 
and subsequently with the various changes of colour. A few of 
the eggs laid by the fecundated moths retained their sulphur- 
yellow colour, and at last shrivelled up. These certainly lost 
their vitality, because from some cause the penetration of seminal 
filaments into the micropyle was prevented, and thus the fecun- 
dation of these eggs was not attained*. 

To the eggs obtained from the seven virgin silk-worm moths I 
directed particular attention from the first, as I was very curious 
to see whether a Parthenogenesis would not be observable at 
least in some individuals of these eggs. I was therefore much 
surprised when I perceived exactly the same well-known change 
of colour which took place in the fertilized eggs soon after their 
deposition, in a far greater number of these eggs than I could 
have hoped, but in the unfecundated eggs it occurred much 
later and more slowly. From some of these virgin silk-worm 
moths I had obtained thirty to forty, from others only about ten 
to twenty eggs, the colour of which slowly altered in comparison 
with the other eggs which had remained yellow, and which gra- 
dually shrivelled up. But this change of colour did not go on 
quite constantly in the same way as in the fertilized eggs. Only 
a few unfertilized eggs passed through the entire alteration of 
colour to the slate-grey ; most of them remained stationary at 
earlier steps of the change, only became reddish or violet, and 
even shrivelled up at last like the pale yellow unfertilized eggs, 

[* This is an insufficient cause, from Siebold's own showing. — "W. S. D.] 



IN THE SILK-WORM MOTTI. 99 

but still a month or two later than these. Unfortunately I had 
not the satisfaction of obtaining caterpillars from the unfertilized 
eggs which had become slate-grey and remained tense, and 
which I had preserved with care through the winter, for they 
also shrivelled and dried up entirely, when the next spring had 
arrived. The same thing happened to me with a great number 
of slate-grey and tense eggs, possessing exactly the appearance 
of fecundated eggs, which were handed over to me by Herr 
Steiner with the assurance that they were laid by virgin silk- 
worm moths. After several months I found these eggs entirely 
shrivelled, without my obtaining a single larva from them. 

In the year 1854, Herr Schmid of Eichstadt, who has occu- 
pied himself for eighteen years with the breeding of silk -worms, 
sent me a quantity of bluish-grey, tense silk -worm eggs, which, 
according to his assurance, were derived from virgin moths. 
From all these eggs caterpillars were actually developed. It 
was of much consequence to me to rear the moths from these 
caterpillars, in order to see whether only a single sex, either only 
males or only females, would make their appearance from all 
these unfertilized eggs which had arrived at development, as in 
the case of the Psychidce and that of the Bees. 

Although I could state no definite motive by which I might 
have been induced to expect beforehand the evolution of male 
moths from the unfertilized eggs of the Silk-worm moth, I must 
admit that, although without any definite ground, I cherished 
the expectation that those silk-worms evolved from unfertilized 
eggs would furnish nothing but male moths. For my justifica- 
tion, I might certainly cite that remarkable notice of Carlier's 
already mentioned (p. 20), which Lacordaire has communicated 
in the following words* : — u Cet observateur a obtenu, sans ac- 
couplement, trois generations du Liparis dispar, dont la derniere 
ne donna que des males, ce qui mit naturellement fin a fexpe- 
rience." Although, as already remarked, this short notice con- 
tains no proof that the observation therein communicated was 
made with the necessary care and exactitude, it now acquires a 
peculiar importance, since Dzierzon's theory has proved to be 
correct. Even in the year 1852, I urged upon Dzierzon himself 

* See Lacordaire, Introduction, Sec. torn. ii. p. 383. 

II L' 



100 PARTHENOGENESIS 

the idea, whether the property possessed by certain female silk- 
worm moths, of laying eggs capable of development without 
fecundation, might not be of use in furnishing aid to his theory 
of the reproduction of the Bees, by means of exact trials and 
experiments. In consequence of this, Dzierzon recommended 
such experiments to the silk-worm breeders*. 

Experiments were hereupon made in this direction in several 
quarters with silk-worms, but up to this time the reports furnished 
of them are still imperfect f. A notice contained in these 
Reports from Dr. Kipp, who had obtained a quantity of eggs, 
and from all these caterpillars, from a Poplar Hawk-moth [Sphinx 
Populi) which had been excluded and kept shut up in a box, 
speaks against Dzierzon's theory, as both male and female moths 
were reared from these caterpillars J. I myself took the greatest 
trouble with the rearing of those young caterpillars which I had 
obtained from the unfecundated silk-worm eggs given to me by 
Herr Schmid, and of fifteen caterpillars which grew large, I 
brought twelve individuals to spin up. The different forms of 
the cocoons at once allowed me to judge that different sexes 
would be excluded from them, and subsequently seven male and 
five female moths actually crept out of these twelve cocoons. To 
convince myself whether these moths produced by Partheno- 
genesis were really sexually mature and capable of propagation, 
I did not prevent them from copulating, which they did imme- 
diately on making their escape. After the performance of copu- 
lation the females deposited a number of eggs, which showed 
themselves to possess vitality, and in the following year furnished 
the same number of caterpillars. Schmid, who had supplied me 
from his store of unfecundated, vitalizable silk-worm eggs, made 
similar experiments at the same time with the rest of the eggs 
which he had retained, and obtained the same result as myself. 
That Schrnid performed his experiments with great care and with 
the necessary caution, appears from the report which he sent 
me on the subject, from which I extract the following as worthy 
of notice. In the year 1853, Schmid captured twenty-four silk- 

* See the Bienenzeitung, 1853, p. 103. 

t Bienenzeitung, 1853, pp. 144 & 175, and 1855, p. 26. 

X Bienenzeitung, 1853, p. 175. 2. 



IN THE SILK-WORM MOTH. 101 

worm moths immediately on their creeping out of the cocoon, in 
order to keep them securely in the virgin state ; they were isolated, 
and found themselves compelled, about the 2nd to the 4th day, 
to deposit their eggs unfecundated. Some hundreds of these 
eggs, which were at first of a sulphur-yellow colour, gradually 
acquired the well-known slate-grey tint, and both in this color- 
ation and in the rest of their appearance exactly resembled the 
eggs of fertilized silk-worm moths. As they thus showed them- 
selves to be capable of life, they were carefully preserved by 
Schmid through the winter, and in the spring of 1854, when 
the mulberry hedges began to get green, they were brought out 
of their winter dwelling-place, in order to dispose them for com- 
plete development in a suitably warmed place. The exclusion 
of the caterpillars took place immediately from 274 unfertilized 
eggs laid by 24 virgin silk-worm moths ; in 270 other unfertilized 
eggs of the same moths the caterpillars were dead before exclu- 
sion. As regards the number of vitalizable eggs, which Schmid 
obtained from 24 unfecundated silk-worm moths, he remarks that 
none of these unfecundated moths laid entirely vitalizable eggs, 
but that sometimes vitalizable, sometimes unvitalizable eggs were 
deposited in irregular alternation one after the other by one and 
the same individual, as immediately after four or ten or fifteen 
vitalizable eggs, the same number or more or less of unvitalizable 
eggs might be counted; sometimes entire masses of eggs were 
laid, amongst which only one, two, three or four vitalizable 
eggs were to be observed. Schmid, like myself, had also made 
the observation that all the eggs laid by fertilized female silk- 
worm moths are not, without exception, vitalizable, but that in 
rare cases single unvitalizable eggs (unfecundated) occur amongst 
the other vitalizable (fecundated) eggs. Several of the above- 
mentioned virgin female silk-worm moths, however, laid nothing 
but unvitalizable eggs. Of the 274 silk-worms obtained from 
unfecundated eggs, Schmid could only keep fifteen alive, in con- 
sequence of the extremely unfavourable conditions of tempera- 
ture which occurred in the spring of 1854 ; he fared no better in 
the same spring with the silk- worms obtained from fertilized eggs. 
Of these fifteen silk-worms twelve were brought to spin up, and 
these furnished eleven moths, amongst which there were seven 
males and four females. Schmid allowed three of these female 



102 PARTHENOGENESIS 

moths tolay eggs without fertilization, but all the eggs deposited by 
these three virgin female silk-worm moths remained light yellow, 
and soon shrivelled, so that they had not been vitalizable. The 
fourth of these females paired with one of the seven males which 
had been reared from unfertilized eggs ; the eggs laid by this 
female after the act of copulation were all, with the exception of 
sixteen, vitalizable, and furnished very fine silk-worms in the year 
1855. Of the six other male silk-worm moths, two were employed 
to copulate with other ordinary females ; these latter also laid 
throughout vitalizable eggs, from which very fine silk- worms w T ere 
produced. In the year 1854 Schmid again selected twenty-four 
female cocoons of silk-w r orms, which were all separated singly 
and strictly inspected. From these, twenty-three females and 
one male escaped ; the latter was removed immediately after his 
exclusion. The twenty- three females deposited their eggs more 
or less irregularly in their solitary cells, and amongst these there 
were only twenty-one vitalizable eggs, the whole of which were 
laid by four of these moths ; all the rest of the eggs had for the 
most part remained pale yellow, or had become reddish-brown, 
and then shrivelled. Unfortunately, in the following year, 1855, 
the breeding of the caterpillars from these twenty-one eggs was 
unsuccessful ; the twenty -one caterpillars had been perfectly de- 
veloped in them, but their exclusion must have been retarded 
on account of want of nourishment, by which they died within 
the egg-shell. In the year 1855, Schmid selected eight female 
cocoons, which were separated and watched with equal care and 
anxiety. They furnished eight female moths, of which seven 
individuals deposited their whole store of eggs in the virgin 
state, whilst the eighth female, notwithstanding the greatest 
exertion, could not deposit even a single egg. Schmid sent me 
the entire harvest of eggs from these moths upon seven strips of 
paper ; there may have been about 3600 eggs ; each of the strips 
of paper contained about 512 eggs, which these moths had 
attached during deposition. On the first strip all the eggs were 
still tense, and furnished with the flat central depression ; forty 
of them had retained their light yellow colour, five had ac- 
quired a slate-grey colour, and all the rest appeared reddish- 
brown. The second strip of paper bore eighteen bright yellow 
and seven slate-grey eggs ; all the rest were of a reddish-brown 



IN THE SILK-WORM MOTH. 105 

colour. The whole of the eggs appeared tense, and with a flat 
depression in the middle ; eight reddish-brown eggs presented 
themselves completely shrivelled. On the third strip there was 
only a single light yellow egg, all the rest had acquired a reddish- 
brown colour. None of these eggs were dried and shrivelled, 
but the central depression was very strongly sunken in a great 
many of them, so that it may be supposed that these eggs will 
very soon become dried up. The fourth strip of paper contained 
only four slate-grey eggs ; all the rest of its eggs possessed a 
reddish-brown colour; only eleven of them were completely 
shrivelled, but others were more or less approaching desiccation. 
On the fifth strip of paper, I could count thirty light yellow, 
tense eggs ; all the rest were of a reddish-brown colour, and only a 
few of these were dried up ; on the sixth strip there were only 
four light yellow, tense eggs ; all the rest were reddish-brown, 
amongst which only a few had undergone complete desiccation 
instead of the central depression. The seventh strip of paper 
possessed only reddish-brown eggs, of which fourteen were 
already completely shrivelled; but many others, to judge from 
the deeply sunken central depression, were on the way to desic- 
cation. Whether caterpillars will actually be developed from the 
above-mentioned sixteen slate-grey eggs, which are still appa- 
rently vitalizable, must be left to time to show. 

If these investigations and experiments have as yet furnished 
no definite result, the reason of this certainly is, that they 
have not been repeated often enough; at any rate Partheno- 
genesis is now firmly established in Bombyx Mori, but never- 
theless the history of the reproduction of this moth merits to be 
further traced in this direction, as this precise object offers 
so many suitable and convenient data for observations and 
experiments. 



101 



CONCLUDING REMARKS. 

Parthenogenesis, as it has been demonstrated by me in 
Pysche Helix, and Solenobia clathrella and lichenella, in Bombyx 
Mori and Apis mellifica, certainly occurs more generally in the 
insect world, than the few examples hitherto discovered lead us 
to suppose. This Parthenogenesis undoubtedly occurs in ac- 
cordance with determinate laws, which have hitherto entirely 
eluded our observation. In Nature, definite objects are probably 
attained by Parthenogenesis, which we can only comprehend, 
when we shall have learnt to know the life and actions of Insects 
in general more exactly, than is at present the case. What an 
important signification Parthenogenesis has amongst the Bees, 
will be seen at once, for without Parthenogenesis the whole 
complicated ceconomy of the Bees, as prescribed by Nature, 
could not exist at all. It is therefore now a task for the ento- 
mologists, to search for further examples of Parthenogenesis in 
the insect world. There are already indications enough, as to 
how and where this remarkable mode of propagation is to be 
sought after amongst Insects. From certain observations which 
we find scattered in various entomological works, it appears, 
that here and there Parthenogenesis dwells unsuspected, and 
that by it the history of the reproduction of many insects is veiled 
in mysterious obscurity. 

Here belongs, amongst others, the statement of Leon Dufour, 
that he has never obtained a male of Diplolepis gallce tinctorue*. 

* See Leon Dufour, Recherches anatomiques et physiologiques sur les 
Orthopteres, les Hymenopteres et les Neuropteres, in Me'moires presenters par 
divers savants a V Acad. Roy. des Sci. de Vlnstitut de France, torn. vii. 184], 
p. 527. Here we find, " C'est un fait fort singulier, mais bien positif, que, 
sur plus de deux cents individus du Diplolepis gallce tinctorice, nes dans mon 
laboratoire de galles renfermees en bocaux, je n'ai rencontre que des femelles. 
Malgre toute mon ardeur a. rechercher des males, dont la dissection m'interes- 
sait au supreme degre, je n'ai jamais pu en rencontrer un seul. Ce qui stimu- 
lait encore davantage mon desir extreme d'etudier ce dernier sexe, c'est que 
les nombreuses femelles soumises a mon scalpel etaient dans un etat avance de 



CONCLUDING REMARKS. 105 

Of the genus Cynips, twenty- eight species are known, which, 
according to Hartig's statement, are all destitute of males*. 
Hartig has inspected nine or ten thousand of Cynips divisa, and 
three or four thousand of Cynips folii, and found no single male 
amongst them. Hartig has even collected Cynips folii for eight 
years, and has never obtained anything but females of this Gall- 
fly ; at the same time he saw these female Cynipidce proceed to 
the deposition of their eggs immediately after their issuing from 
the galls. 

The reproduction occurring amongst certain of the lower 
Crustacea, which it has been attempted to refer to Alternation of 
Generations and nurse-formation, may also turn out on closer 
investigation as true Parthenogenesis. As is well known, the 
genus Apus amongst the Phyllopoda only presents females ; 
Zaddach indeed has supposed that he discovered male indivi- 
duals in Apus cancriformisf, but I have called this statement in 
question, on account of the want of positive proof J. Of the 
Phyllopodous Limnadia gigcis also, no male has yet been dis- 
covered §. In Daphnia too, it appears not to be nurses but 
female individuals which perform the business of reproduction 
by Parthenogenesis ; for Lievin, who has compared with each 
other, female Daphnia taken in copulation, and others which 
were independently prolific, could not find the least distinction 
between the two kinds ||. Of Polyphemus oculus, we as yet only 
know female individuals^. 

fecondation, quoique je procedasse a leur vivisection immediatement apres 
leur sortie de la galle." 

* See Zweiter Nachtrag zur Naturgeschichte der Gallwespen in Germar's 
Zeitschrift fur die Entomol. band iv. 1843, p. 397. 

f See Zaddach, De Apodis cancriformis anatome, 1841, p. 53. 

X See my Lehrbuch der vergleichenden Anatomie der wirbellosen Thiere. 
1848, p. 495. note 8. 

§ See Brongniart, Memoire sur la Limnadia, in Memoires du Museum 
d'Histoire Naturelle, toni. vi. 1820, p. 89. " II reste un point tres curieux it 
e'claircir dans l'histoire de ces anitnaux, c'est leur mode de generation ; il est en 
effet fort remarquable que sur pres de mille individus que nous avons vua a 
Fontainebleau, tous portoient des ceufs soit sur le dos, soit dans le corps.*' 

|| See Lievin, Die Branchiopoden der Danziger Gegend, in the Xeuesten 
Schriften der Naturforschenden Gesellschaft in Danzig, band iv. heft. 2, 1848, 
p. 26. 

IT See Jurinc, Histoire des Monocles qui se trouvent awe environs de Center. 



106 CONCLUDING REMARKS. 

Amongst the Mollusca also, phenomena occur, which indicate 
the possibility of a Parthenogenesis ; thus amongst others, Vogt 
was able to observe the commencement of development in the 
eggs of a female Firola laid without fertilization, namely a seg- 
mentation of the yelk proceeding to a certain extent*. 

From these intimations, it appears that reproduction by Par- 
thenogenesis is far from being sufficiently exhausted by my 
investigations, and is still capable of receiving many an addition. 
Even now, however, we may declare that the hitherto generally 
admitted proposition of the fecundation theory, that the deve- 
lopment of the eggs can only take place under the influence of 
the male semen, has suffered an unexpected blow by Partheno- 
genesis. It has indeed been attempted to avoid this, and hold 
on to the old important proposition of the theory of fecundation, 
by supposing that in many cases a single fecundation may act 
through several generations ; but much is not gained by this new 
proposition, as by it many of the phenomena occurring with 
Parthenogenesis can by no means be explained. On the other 
hand, it may appear too bold to assign already to Partheno- 
genesis a definite position in the history of the reproduction of 
animals, before it is thoroughly explored to a much greater extent 
and in all directions. Victor Carus has attempted to bring Par- 
thenogenesis into combination with the care of the brood (Neo- 
melie),and has established the proposition f: the female form must 
be fertilized, and indeed by the male form, but for the develop- 
ment of the latter J no repetition of the fecundation is required, — 
the male germ developes itself in the manner of a bud or nurse. 
This proposition, however, cannot be applied to all the cases of 
Parthenogenesis cited by me ; properly speaking, it only suits 
the Bees ; in the other cases only females are evolved from the 
unfecundated germs, and in Bombyx Mori, females and males 
simultaneously in indefinite numerical proportions. 

In Psyche Helix, Solenobia clathrella and lichenella, in oppo- 

1820, p. 146. " Quoique je ne doute pas qu'il n'y ait des males dans cette espece 
comme dans les precedentes, je dois annoncer que dans le petit nombre d'indi- 
vidus que j'ai trouves, ou eleves, je n'en ai reconnu aucun." 

* See Yogt's Bilder aus dem Thierleben, 1852, p. 217- 

t System der thierischen Morphologie , 1853, p. 280. 

% Op. cit. p. 5/. 



CONCLUDING REMARKS. K)7 

sition to the Bees, the females after copulation will probably de- 
posit those fertilized eggs from which only males are developed. 

Hence it may happen that here and there in the open air we 
find the male and female individuals living together by them- 
selves, and separate from each other. With this, the observa- 
tion of Zinke stands in perfect accordance*, that many Sac- 
bearers only occur in separate sexes during their larva and pupa 
state, and that where one sex is met with, the other may be 
sought for in vain. A communication made to me by letter by 
Heyden may also find an explanation by this : Heyden observed 
in the genus Coccus that the males live in company separated 
from the females, until they are perfectly developed. 

The male individuals in the larva state probably lead quite a 
different mode of life in Psyche Helix, and might in consequence 
have hitherto escaped the observation of those entomologists 
who hoped to find the caterpillars of the males of Psyche Helix 
as Sac-bearers with a convoluted dwelling. For these assertions 
of mine, which are only expressed as suppositions, a support 
may be found in an observation which was made by Leon 
Dufour. From a particular gall, he always reared nothing but 
female individuals of the Hymenopterous insect Stomoctea, but 
was much astonished when he obtained nothing but males of 
this insect from the pupa of a Tenthredof. 

* See Germar's Magazin der Entomologie, i. 1813, p. 31. 

t See Leon Dufour, Recherches, fyc, p. 528. To the observation that he 
had only been able to obtain females of Diplolepis gallce tinctorial, he adds the 
following interesting remark:— " J'engage les entomologistes a nous faire 
connaitre le male de cette espece, la plus grande de nos contrees. II serait 
bien curieux de constater si les ceufs qui ne produisent que des males sont 
tous pondus dans une espece de galle, et ceux des femelles dans une autre. 
Je puis citer a l'appui de cette question un fait digne de remarque. En juin 
1833 j'obtins, des galles de la Scrophulaire canine, produites par YEulophus 
Verbasci, un petit Hymenoptere du groupe des Cynipsaires, appartenant a un 
genre nouveau, que ses mandibules pectinees m'ont fait appeler provisoire- 
ment Stomoctea. II en naquit au moins une cinquantaine d'individus, mais 
tous, sans exception, femelles. En juin 1834, je ne fus peu surpris de voir 
eclore d'une chrysalide de Tenthredo,\)\a,cee dans un verre clos, une quarantaine 
d'individus de la merne espece de Stomoctea, tous du sexe masculin. Que 
n'avons-nous pas a apprendre encore sur les Hymenopteres gallicoles et 
pupivores, soit quant a la determination des especes, soit quant a leur genii' 
de vie et aux merveilles de leur organisation viscerale ! " 



108 CONCLUDING REMARKS. 

From these fragmentary statements it will be seen what a 
wide field still stands open for the investigation of Partheno- 
genesis, accompanied as it is by such extremely peculiar pheno- 
mena ; in no case, however, will this portion of the history of 
the reproduction of animals, enveloped as it is in so much ob- 
scurity, allow itself to be quickly and easily cleared up ; for, as 
regards Psyche Helix, for example, the entomologist desirous of 
knowledge, and seeking after the males of this moth, must arm 
himself with patience in order to arrive at the goal ; for if, in 
this case, which is probable, Parthenogenesis has its hand in the 
affair through several generations, as only a single generation of 
this moth, the male of which has been sought in vain for the 
last seven years, is produced annually, we should still have to 
wait some years before a male generation at last makes its ap- 
pearance, and reveals the mystery interwoven with this moth. 



109 



EXPLANATION OF THE FIGURES. 

Fig. 1. Caterpillar-sac of Psyche Helix, Sieb., seen from the side. 
Natural size, b, opening which has been left by an escaped 
Chalets. 

Fig. 2. The same sac with the caterpillar; a, aperture which the 
caterpillar always leaves in this spot during the enlargement 
of its sac. 

Fig. 3. The same sac seen from above ; a, as in the preceding figure. 

Fig. 4. Full-grown caterpillar of Psyche Helix. Natural size. 

Fig. 5. Female pupa of Psyche Helix. Natural size. 

Fig. 6. Sac with caterpillar of Psyche Helix. Enlarged. «, as in 
fig. 2. 

Fig. 7. Caterpillar of Psyche Helix. Enlarged. 

Fig. 8. Maggot-like female of Psyche Helix. Natural size. 

Fig. 9. The same enlarged. By transmitted light the urinary vessels 
appear black under the microscope, and not yellowish-white 
as by direct light, c, head ; d, a portion of the urinary 
vessels shining through the integument. 

Figs. 10, 11, 12. Three figures copied from Reaumur 's Memoir es, 
torn. hi. pi. 15. figs. 20-22. Enlarged sacs of Psyche Helix, 
which Bazin found upon sandstone in the vicinity of the 
Hermitage d'Estampes. 

Fig. 13. Chalcis nigra, Koll., from Psyche Helix. Natural size. 

Fig. 14. The same insect enlarged. 

Fig. 15. Caterpillar-sac of Psyche Planorbis, Sieb., seen from above. 
Natural size. a, spot in which the walls of the sac are 
deficient, as in fig. 2. 



110 EXPLANATION OF THE FIGURES. 

Fig. 16. The same sac from the side. 

Fig. 17. The same sac seen from below ; «, as in fig. 15. 

Figs. 18, 19. Sac of Helicopsyche Shuttleworthi, Bremi. Natural size. 

Fig. 20. The same sac seen from above, enlarged. 

Fig. 21. The same seen from the side, enlarged. 

Fig. 22. The same seen from beneath, enlarged. 

Figs. 23, 24. Vahata arenifera, enlarged and copied from Lea. 

Supplementary Observation. — At my last visit to Zurich I saw in 
Bremi' s collection the cases of a third larger species of Helicopsyche, 
which Bremi obtained from Shuttleworth and has named Helicopsyche 
Colombiensis. These cases come from Puerto-Caballo ; they have a 
transverse diameter of 1^ lin. and a height of 1-& lin. Rhenish, and 
are manufactured out of comparatively very coarse, rusty-brown stones. 
With regard to Helicopsyche Shuttleworthi, Bremi informed me, that 
the cases of this Phryganidous insect have now been found also on the 
Lake of Geneva. 



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